Router help

[fuzen]

I've been experiencing my internet being "cut off" up to 4 times a day. It will just stop and I'll go and reset the router and then everything works fine. I'm not sure what the problem is, it's a linksys WRT54GS with firmware v3.37.6, Jan. 6, 2005. I figured that maybe an update to this might fix this problem but not sure how to upgrade the version. Anyone have a clue what to do to fix this problem?