While you are waiting for your longarm, you might want to try quilting standing up. I place my machine on my cutting table and put a styrofoam table around it to create a flat surface (directions on Youtube). This is *much* easier on my neck and shoulders, so I can quilt much longer without getting fatigued.
You might want to join the Yahoo group homequiltingsystems for advice. This is a large, active group of home quilters with a wide variety of midarm and longarm setups. The rule-of-thumb advice on that group is to research setups for a year before actually buying one, as there are a lot of choices out there.
Also, if you want to be more economical, you might want to start out with a homemade setup. I am currently looking at the following possibilities:
http://www.easyquilter.com
http://buildaquiltingframe.weebly.com/index.html
http://machine-quilt-frames.blogspot.com/
I had the opportunity to try out an EasyQuilter at a local quilt show and loved it. You spray baste the quilt. The setup I tried was the 5.1 version with a Janome 1600P machine (very fast stitching speed). When we get some time, my dh plans to make up a system to my specs. I figure the frame will cost around $200 and the machine about $600.