Get Tortoise CVS commits by a particular user

Here's how you would be able to get the updates made by a particular CVS user from a date range.

cvs log -wusername -S -N -d"datestart<dateend"

an example:
cvs log -wjohnnyb -S -N -d"2012/1/1<2012/11/30"

Here's a copy-paste of how to use cvs log from http://evscm.org/manual/html/log.html

log--Print out log information for files
Synopsis: log [options] [files...]
Requires: repository, working directory.
Changes: nothing.

Display log information for files. log used to call the rcs utility rlog. Although this is no longer true in the current sources, this history determines the format of the output and the options, which are not quite in the style of the other cvsnt commands.
The output includes the location of the rcs file, the head revision (the latest revision on the trunk), all symbolic names (tags) and some other things. For each revision, the revision number, the author, the number of lines added/deleted and the log message are printed. All times are displayed in Coordinated Universal Time (UTC). (Other parts of cvsnt print times in the local timezone).

Warning: log uses -R in a way that conflicts with the normal use inside cvsnt (the section called “Common command options”).

log options
By default, log prints all information that is available. All other options restrict the output.

-B bugid 

Only select revisions which are related to a single bug.

-b 

Print information about the revisions on the default branch, normally the highest branch on the trunk.

-d dates 

Print information about revisions with a checkin date/time in the range given by the semicolon-separated list of dates. The date formats accepted are those accepted by the -D option to many other cvsnt commands (the section called “Common command options”). Dates can be combined into ranges as follows:
d1<d2, d2>d1Select the revisions that were deposited between d1 and d2.
<d, d>Select all revisions dated d or earlier.
d<, >dSelect all revisions dated d or later.
dSelect the single, latest revision dated d or earlier.
The > or < characters may be followed by = to indicate an inclusive range rather than an exclusive one.
Note that the separator is a semicolon (;).

-h 

Print only the name of the rcs file, name of the file in the working directory, head, default branch, access list, locks, symbolic names, and suffix.

-l 

Local; run only in current working directory. (Default is to run recursively).

-N 

Do not print the list of tags for this file. This option can be very useful when your site uses a lot of tags, so rather than "more"'ing over 3 pages of tag information, the log information is presented without tags at all.

-R 

Print only the name of the rcs file.

-rrevisions 

Print information about revisions given in the comma-separated list revisions of revisions and ranges. The following table explains the available range formats:
rev1:rev2Revisions rev1 to rev2 (which must be on the same branch).
rev1::rev2Revisions between, but not including, rev1 and rev2.
:revRevisions from the beginning of the branch up to and including rev.
::revRevisions from the beginning of the branch up to, but not including, rev.
rev:Revisions starting with rev to the end of the branch containing rev.
rev::Revisions starting just after rev to the end of the branch containing rev.
branchAn argument that is a branch means all revisions on that branch.
branch1:branch2, branch1::branch2A range of branches means all revisions on the branches in that range.
branch.The latest revision in branch.
A bare -r with no revisions means the latest revision on the default branch, normally the trunk. There can be no space between the -r option and its argument.

-S 

Supress log output when no revisions are selected within a file.

-s states 

Print information about revisions whose state attributes match one of the states given in the comma-separated list states.

-T 

Display dates and times in the log output in Local time rather than GMT.

-t 

Print the same as -h, plus the descriptive text.

-w[logins] 

Print information about revisions checked in by users with login names appearing in the comma-separated list logins. If logins is omitted, the user's login is assumed. There can be no space between the -w option and its argument.

-X 

Supress extended information generated only by CVSNT servers. This can be useful with some frontends that cannot parse the extra output.

-x 

Generate full output. This is the default unless configured otherwise on the server.
log prints the intersection of the revisions selected with the options -B,-d, -s, and -w, intersected with the union of the revisions selected by -b and -r.