It will be a good book for you. If you haven't done so already, go to the books download area, and download the Bonus Chapter: Appendix D - C# for C++ Developers
Regarding the upgrade, then it depends on your situation. If money is no issue, upgrade. If you would rather buy flowers to your girlfriend, then stick to 2003. You can always upgrade later.
Wether to get professional or standard again it depends on your situation.
You can compare the two here: