Wifi connectivity problem

Hi,
I have a connectivity issue between my Curve and my home router Dlink dl-524. The thing is that the phone connects to the router and I can see it in the router setup page, however, I can't get any Internet on the Curve. There have been only 2 breakthroughs - when I upgraded my OS (currently the latest hybrid from Willyboy). After an upgrade I can connect and, albeit slow, I get Internet, but only for a few minutes and then it is gone (without any notification - the wifi icon stays and I am still connected to the router). The wifi icon is always grey, but that doesn't seem to be a problem since I can connect to any other hotspot flawlessly. At first I thought it was a problem in the router, but now since it worked after OS upgrades, I think that maybe some settings that the phone receives confuse it and the connection drops.
Looking forward to some solutions. Thanks!

PS.
I don't have a data plan, but I am referring only to the browser and not other applications.