How to print duplex on Ricoh pro C5100s

Hi guys,
I have some problem, my ricoh pro c5100s can not print duplex on 300gsm paper. But when I need to make ,for example, some bussines card with print on both side, I must use 300gsm paper.
First I print on one side, than turn the paper manualy, and print on the other side. But I cant aligned both sides. I still have some deviation, 1 or 2 milimeters. Is there an easier way to impose files for printing on both side? I use a program InDesign. How do you do it?? Which software?

Thanks a lot! :)