Hi bogies
If it were my car, I would not buy a new headunit until finding out why the fuse was blowing. Once corrected, your current headunit should work (subject to it not been the cause of blowing the fuse)
If you then want to install a new headunit, there are a lot of write ups on the forum, which even tell you what you need and have to do to install the headunit
Xtrons do headunits and facia etc....
But if you planning on fitting a new headunit without resolving the fuse issue, your new headunit may not work and you will be in same position you are now
Many thanks
John