A wireless router question

[Zevico]

I've just gotten a wireless router and have trouble playing internet games--ie. warcraft 3 (DOTA if you're really curious). I've never had trouble accessing them before with my previous router (which was not wireless). I use a Macintosh laptop which has always been able to play these games without a single problem before. The router is made by the Netgear company; it is 54mbps and is model WGR614 V5
The trouble is that, firstly, connecting to battle.net (the game server) is not always succesful now that I'm using a wireless router (I'm told that I need to connect my modem to the internet. problematic considering I use a cable modem that's always connected). Secondly, if I do connect succesfully, half the time I can't access any games--being told that the games themselves 'do not exist'. Usually this means that the games have already started a while ago and I'm trying to join a game already in progress, but now I'm convinced that this must be another wierd connection problem. Thirdly, if I do enter a game succesfully, I disconnect from it after about 5 minutes, being told that "I have lost my connection to battle.net".
Please help me apolyton tech people...without your aid I will be bereft of net games forever...