Is this something I can do in the back yard? Do I have to remove anything else to get to it? Do I need special tools to rent?
You first need to soak the strut "pinch" bolts with blaster for at least a week. Have an acetylene oxygen torch handy to heat the bolts. You'll need to rent a coil spring compressor for your exact car from Advance Auto Parts or Auto Zone. Rear springs are always sold in pairs and that's the way to replace them. You'll have a lop-sided car if you don't. You'll need a box full of 1/2 metric shallow well sockets.
You'll also need a Haynes or Chilton's service and repair manual for your specific car to have an idea of the sequence of removal of the sway-bar links and strut "pinch" pinch bolts.
If you have no prior experience of doing this type of work, I would say that you should take the vehicle to a reputable shop. By the time you buy the tools needed and rent the spring compressor, and hope for the mounting bolts to come loose without heat (or possibly heating them with and oxy/acetylene torch) , especially the lower pinch bolt, you could easily end up spending the better part of a day doing this job in the backyard..
Take Country Boy's advice if ya want , but I would take it to a shop.