Glad you got it working.
FF 3.5 can be replaced by a newer version. Either by using the update feature of the browser or - much better - by installing it to /mnt/home, if you have a frugal install.
Just get the tar.gz from the mozilla site
unpack it to /mnt/home and change the path in the desktop icon to read /mnt/home/firefox/firefox.
Don't forget to delete the old FF 3.5. folder under /usr/lib.