Microsoft multimedia Wireless Keyboard not working properly

Hello all. I am a new user to the Mac community, so please help me step-by-step. I have this strange problem: my keyboard layout is a bit messed up. I have tried installing the IntelliPoint driver, but there are some keys that don't work, and others that are different. As I am Portuguese, there are some keys like the at that don't simply work. I have found no solution until now. I hope some of you help me, and thank you!