So i will need to get version 7 as well as the latest version in case there are translation problems?
You may well have no issues. But you always have the option to rendering to audio and midifiles and getting your old stuff into a "new" project that way. This is good practice anyway, as it means you project are not reliant on a whole load of third-party dependencies just to load.
If you do decide to track down a second-hand copy of Logic Pro 7, it *needs* to be 7.2.x, as that was the first version to run on Intel machines. Do not get 7.0.x or 7.1.x, as you will find it next to impossible to track down a copy of the 7.1 to 7.2 upgrade and it will just give you more headaches than it's worth.
And be aware that this version was released before snow leopard and certainly isn't designed for it (though it does run, as far as I can remember.) And you'll need the dongle/XSkey.