you have an automatic. the code will be located on the transmission bellhousing - see picture:
or, call the dealer and give them your vin - they will pull it up.
or, look at the sticker in your trunk under the carpeting - will be listed there.
sounds like the trans is toast, as it is cheaper to buy new/used than rebuild. once they start to slip, even if the fluid is low and is topped off, it is usually too late...