If the cookie is generated from script, then you can send the cookie manually along with the cookie from the file(using cookie-file option). For example:
# sending manually set cookie
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Cookie: test=cookie"));
# sending cookies from file
curl_setopt($ch, CURLOPT_COOKIEFILE, $ckfile);
In this case curl will send your defined cookie along with the cookies from the file.
If the cookie is generated through javascrript, then you have to trace it out how its generated and then you can send it using the above method(through http-header).
The utma utmc, utmz are seen when cookies are sent from Mozilla. You shouldn't bet worry about these things anymore.
Finally, the way you are doing is alright. Just make sure you are using absolute path for the file names(i.e. /var/dir/cookie.txt) instead of relative one.
Always enable the verbose mode when working with curl. It will help you a lot on tracing the requests. Also it will save lot of your times.
curl_setopt($ch, CURLOPT_VERBOSE, true);