Help/Advice with Airbag Seatbelt light Reset (E90)

Soo, just like the title says...my 2006 325I seat belt and airbag light came on and wont go off..

Long story short, i had something under the seat that i'm fairly sure triggered it...

I've been looking at a bunch of different diagnostic tools that are all like 300 bucks +..
I came across an OBDII cable that i beleive will work witn INPA (not that i know much about inpa)

http://www.amazon.com/Loftek-Interf...qid=1369934974&sr=8-2&keywords=inpa+cable+bmw

I linked the cable...It should arrive Saturday. Would someone verify that this cable is actually going to work? I've read mixed reviews on it...

My second question is...Where would be the best place to download the INPA software?

Any help would be greatly appreciated!

Thanks!_a_