Did it use to work fine with the wireless card you are using now? Is it losing connection to the wireless all together?
You can eliminate your internet connection as the problem by running two simultaneous ping tests, one on the gateway IP, one on an internet IP. If the Internet IP starts dropping packets and the gateway does not, you got internet issues. If both drop at the same time, you got wireless issues. You can get your gateway IP by hitting Start-->Run-->type: cmd -->hit enter-->type: ipconfig --> hit enter--> read gateway ip, then type: ping gatewayip -t -->hit enter this will start a continuous ping to your gateway IP on your router. Open a second dos window (start, run, cmd) while pinging the gateway in the first dos window ping an internet IP in the 2nd window- type: ping 68.178.232.193 -t This is an internet IP that you can ping. Wait for packets to start dropping in either window.
If both ping tests start to lose packets at the same time (a router/wireless issue) see if the manufacturer has a newer version of firmware for the router. Make sure your laptop has the latest driver for the wireless card. If it still does the same thing, see if sitting closer or farther from the router has an effect on the situation. Microwaves, HVACs, cordless phones, and wireless cameras can all cause inteference. When my AC comes on in my house, my signal drops down to "very good".
If it previously worked fine and nothing has really changed, chances are good that the router needs to be chunked or flexed on. I've gone through a D-Link, Linksys, and most recently a Belkin. They all just crapped out in one way or another and I've seen countless other routers crap out in similar ways. I even keep mine on battery backups and that doesn't help. They are throw aways unless you shell our for a Cisco or something (not a Linksys with Cisco's name on it).
Seth