Imac Not Working With Airport


Ok, I have an iMac G5 running Tiger with all the latest updates. The problem I am having is Airport. The internal card drops the network ALL THE TIME now. I am "connected" to the network but I have little if any internet access. When I do have access, it is very slow. We are talking dial up speeds. This is bad because I am on cable with an 8mbs connection. My PC gets that speed, but my mac never has. What is a solution to my problem? I have already contacted Apple several times and their solutions solved the connection issue, but not the speed. I have deleted the System Configuration folder already and did that whole bit, as well as power cycling everything. Nothing is working. Any help would be greatly appreciated. Thanks!

PS I am using a D-Link DI254 router and I have had no problems with it prior to this morning. Nothing has been done to the computer before that. As a matter of fact, it was asleep.