To determine current Firmware version:-
Logon to router via your web browser using usual default address of
http://192.168.0.1 , and enter default admin account and password as:
admin
password (unless it has been changed!)
then goto 'Maintenance > Router Status' to view firmware level.
User Manual is available here:
http://support.netgear.com/product/DGND3300v2
Firmware versions available here:
http://downloadcenter.netgear.com/ (you need to enter model number as DGND3300v2)
But like OG says, 'if it ain't broke then don't fix it!'