Just google for the springs (H&R) and you should be able to find them. I got lots of hits when I googled just now.
Bolt pattern for the rims is 5x112.
When I had my '00 Eurovan, I had 17x8 rims ET35 with 245-45-17s on them and the sliding door *just* cleared the rear wheel and tire.
Make sure whatever rims you pick that you can get tires that are at least a 98 load rating. Anything lower is too risky.