Macbook Pro (mid 2010) connection issue?

I purchased my Macbook Pro from an Apple Store 3 weeks ago. Everything was fine up to the last week or so. I am connected to a Belkin 54G wireless router. The connection works for a while, and then I can't browse websites, or ping my router. My Dell laptop works fine when my Macbook doesn't. The 4 bars on the wireless icon are all black even when the connection doesn't work (no web browsing/pinging). I turn the Airport off and then on, and I can browse the internet again. This is extremely annoying. I also connected to a Netgear router and got very slow to no connection whatsoever. Again, the Dell worked fine. All the firmware updates on the routers are up to date. Does anyone have a clue why this is happening?