The router I've got worked very well for the first 6 months or so, then we started having problems of it crashing, similar to your problems. I ended up putting DD-WRT (a new firmware) on the router, and we haven't had any problems in about a month. It unlocked some new features as well, and I did turn up the power to the antennas to push the signal a bit further.
I looked it up at the
DD-WRT Router Database and of the 3 different model versions, only the 1.0 is supported. Try turning the router upside down and looking at the sticker. If it says V1.0, or doesn't say it has a version, it's probably the version 1.0 router. Unfortunately, if it's anything newer, you're out of luck with DD-WRT.