I agree with everything Gaynor said; definitely no swimming due to bacteria. Gentle walk around the block is ok I would think. I'm 4 weeks and I'm walking into town now, albeit slowly.
I had a tummy tuck only and was told no exercise til at least 6 weeks then it has to be gentle, no ab crunches etc.
If you have any queries, you can always give the hospital a call; they will be more than willing to give you any advice.