Most universal remotes won't control higher functions (such as the menu), they usually only support basic functions like change channels, volume and power. If your remote has been coded properly to turn your TV on and off, and you can adjust volume, you should be able to go into the TV menu from the front panel buttons and do an auto-scan for channels. Once this is done, you should be able to use your new remote to select channels.
Get a One For All 8910. If it won't do all functions out of the box, it can be upgraded over the phone. If it still doesn't do all functions, they can e-mail advanced functions for most codes. I haven't found anything it won't control yet. You can get one for around $20 at Amazon, $10 or so for a refurb.