For your Wi-Fi, take a look at
www.jwire.com for locations and costs.
As for your home wi-fi issue. First thing first. Remove all encryption from your router, remove MAC filtering (if you use it) and make it visible just to test the M600 will connect. If it does, turn on encryption again but keep visible for the time being.
When entering your WEP key, you must use the same case throughout in your hex. Some routers see H7 and h7 as completely different, so try both methods to see which your router needs. Had a similar issue with my router and Ipaq and the router wanting the ipaq as lowercase, yet everything else is uppercase. Go figure.
Once you're working, you can hide your router again, and reapply MAC filtering (if you use it - be sure to add the M600 first though!).