ip2nation - resolve IP to country - country-based redirect
this is exactly what you need, straight from the example page..
you simply query the database (as shown in the example - the same exact query should to the trick for you, too)
the you use a switch statement to redirect people based on country. you can add, as per the example, any country you want, just make sure you use the correct country code (ie, se is for Sweden, etc.); just take a look at the source code, you'll probably figure it out
to be honest, it's kinda self-explanatory.. if you can't copy/paste this code and do minor modifications to it, in order to suit your needs, then maybe you should learn some basic PHP programming (or hire someone, dunno)
anyway, put this code at the top of your page (edit index.php of your WP theme) and it should work.
post back if you encounter any problems.