Hi Tony,
A year or two ago I had essentially the same issue as you, how to get a wireless connection to the garage so my Rio receiver could connect to the house network and ultimately my Rio Central to stream tunes in the garage.

All my stuff was/is Linksys, so I wanted to stay with their products to make it easier to configure and for compatibility, etc. I probably didn't have to do that, but I did.

The only product of theirs that would do the job for me was two WAP54G units. I already had a WRT54G Wireless G Router, but nothing I bought would connect the Rio to it and work properly. Like you, I returned several boxes before I bit the bullet and bought the two WAP54G units. They worked fine right out of the box...

Yeah, I know, it cost more than the Rio to begin with, but I did get it to work...And it's great to have Rio Central tunes in the garage when I'm working out there...

Good Luck on your project.....

Randy