Guess this reply is now late but I just arrived here... so... it may help someone in the future or even you.
The best way to stay with your Tomtom version is to get any chinese navigation device that can run WinCE 5.0 and remove the existing sofware off that device to make room for your Tomtom. Once you get that done it is time to activate your Tomtom and maps. I am currently trying to run Tomtom 7.450 on a WinCE 6.0 device I just bought. But I am a die hard guy
so if you are not into spending loads of hours into testing how to make that combo work then stick to the WinCE 5.0 and Tomtom Navigator 7.xxx
PS: Never throw anything into the bin. One day you may discover new things that will allow you to use it again. I got loads of random hardware that is mostly obsolete but kept ending up reusing most of it later again for random reasons. The older the things gets the harder it is to find and succeed in your endeavour. Especially when you threw away your hardware.