Is there a place near you that offers Hydrobics (water aerobics). Since you're in the water, even with jumping, there is negligible impact, but if you get a good instructor, you WILL get a good workout! If there is a 'Y' near you, check that out. Some colleges also offer classes to the community.
I will check out the "Y" in my area and in the surrounding areas to see if that is available. Thanks.