Congratulations on your Hobie! First, you have the correct Drive, but the masts (rods holding the fins) are bent. They should look more like this (disregard the fin mis-match):
After removing the fins, you can bend the masts forward by hand, or if you have one, use a 3/8 ID pipe. The Drive probably needs cleaning and lubing also. Use "search" on this site to see what you can find.
Your rudder is not upgradable, but you can restring it using Spectra (what Hobie currently uses. I have an old operator's manual -- when I return next week, I'll try to find it and send some diagrams. Hobie may still carry your missing parts. Here are a couple if you are missing them:
Have fun with your new toy!