Sounds like you are starting in the right place with telnet.
Does the wireless router allow all ports? First glance, TCP:1433 is probably blocked. Try unblocking all ports, then you can work your way back to tighten which ports you need.
If that doesn't help, try connecting using named pipes. From a UDL file or managment studio/enterprise manager, test connecting to NP:<servername>. You can force TCP using TCP:<servername>[,port].
Check out this link for other ideas...
http://support.microsoft.com/kb/328306
Adam Gossage
Lake Wylie, SC, USA