BATTERY POWER FOR THE AF MOTOR SHILD ! WHAT HAVE YOU USED ?

I had a nice 12v 1.2 amp battery supply… problem is its a lead core one and it turned out that befor i even got my bot finished cuz im still working on the stepper 2 at once thing that the battery was to heavy to move soo i hunted down some battery packs they are 7.2 for r/c cars … i bought the lowist amper pacs witch helped cost being i paid 6 bucks with charger from raido shack <(ass holes told me it was 30 on the phone lol ) ok so i tryed it out now i have 7.2 volts and 2000 mill amps witch is just 2 amps if i rember right but the power of the 14 volt steppers is not enought with one of theses to move with out the 12v power i had soo i was thinking about useing 2 packs in sieries to get like 14volts but what will my ampers be 4000 (4amps ) or still 2000 (2amps) ? becuse the af motor sheild only takes like 1.6 amps i think… soo ill for sure burn it out if its 4amps …heres a photo of the added heat sink and fan how much extra do you think it can handel with this mod-cooling