are you sure that XFree86-3.3.6 support your video card? some new cards or new versions of drivers are only supported by XFree86-4.x (better use the lates, 4.10.6?).
another option is to re-compile your kernel if you are sure your card is listed in the kernel config file. check /usr/src/sys/i386/conf/LINT to see if it is there. You may need to check the kernel conf file (either GENERIC or you have customized your own) to check those devices for laptops.
If your card is definitely supported, but not compiled into your kernel, recompiling your kernel by adding a device option to the configure file should not be too hard. Good luck.
