GPS/GPRS problem

You can't add variables to this:

mySerial.println("AT+HTTPPARA=\"URL\",\"www.mysite.com\\dat.php");// setting the httppara, the second parameter is the website you want to access

You could do something like this:

char buffer[120];
sprintf(buffer, "AT+HTTPPARA=\"URL\",\"www.mysite.com\\dat.php?val1=%d&val2=%d", val1, val2);
mySerial.println(buffer);

assuming that val1 and val2 are defined as ints.

If you had something else in mind, we're not mind readers.