Since sendsong in installer.app doesn't work on 1.1.3 yet, here's a program to use if you can't wait. Installation is a lil complex, so hopefully you get the instructions on there.
1.) Install 2.1.3 program.
2.) replace iPhoneRingToneMaker.exe with patch one
3.) reigister/enter serial number
4.) re-install 2.1.3 program again.
Replace $ with S