How to change default port for T-SQL Debugger
I don't think it's possible to change the TCP port used by T-SQL Debugger.
You can use an application such as RelayTCP and port forwarding rules on your router to achieve what you want. It's difficult to give specific recommendations without knowing more about your network topology.

It may be easier to set up a VPN to your site and then run T-SQL Debugger over VPN (I assume that LAN-local connections to TCP 135 will not be blocked).