Dlink wireless problem - Please help

So I got tired of toting my 25ft ethernet cable out to the porch everytime I wanted to browse the web while sitting out there. I bought a dlink 4 port/wireless(b) router and a dlink USB receiver for my iBook. I hooked up the router to my existing Linksys router and hooked up my Sawtooth to the dlink via ethernet cable. That works wonderfully - no problems at all. I didn't even have to use the included software to get it to work. It took a little more time to get the wireless part to work with my iBook, but I finally got it working too. But I am still having some glitches that I think may be tied to the USB port, but I wanted to check with you guys to be sure.

Whenever I try to do some heavy downloading, the receiver in the USB port seems to freeze. Meaning, I can no longer do anything that is tied to the internet - no browsing, no iTunes, no e-mail. I can open each of these applications, they just can't connect with any server. When I check the status, it says everything is fine. I can restart the laptop and I will be able to use everything again. I also learned last night that I can pull the receiver out of the USB port and plug it back in and then I am up and running again. Is this just a weakness with using a USB receiver? I can deal with that, I just want to be sure that it is not a router problem. If it were a problem with the router, wouldn't I also be having problems with the ethernet ports as well? The hardwired portion works fine though. Anybody have this same problem or some ideas that I can try to keep from locking up? Any help is greatly appreciated.

Yes - mine is a wireless network adapter - the dwl-122 to be exact. Glad to know I am not the only one having problems. So then could I get a different wireless adapter/receiver to plug into my iBook and still use the dlink router? Any recommendations as to a good receiver to plug into my laptop?