You should be able to plug your 804 into another router with faster speeds. Just run everything else in the house off of that to get your high speed LAN
I run a LinkSys WRT54GL wireless router behind a Netopia R-3100-U ISDN TA/Router. We do local file transfers at very high speed over the LinkSys wireless. I even run a remote desktop downstairs on my laptop, with my desktop upstairs serving. Works great.