I would check out the Englander Add on furnace. I had one for a few years. I got rid of it a few years ago because we have alot of power outages in the winter and it required power to heat really well. ( to run the blower )
But, it worked great and i only paid $600 brand spanking new for it. Lowes has them. Clayton also makes a quality one.
With you having a ranch stly house it would be really easy to run the duck work. I just went to the local hardware store and bought regular single wall 8"stove pipe to run as duct work. I might have had $40 in all the duct work.
I don't think a normal woodstove is going to heat your house all that well. Not being in the garage anyway. The heat has no way of making it upstairs. I would just break down and buy a new or used add on furnace if you can find them. ALthough you will have to put some money into this project, it will pay itself back in just 2-3 years depending on your fuel bill now. Any time after payback is just money in the bank.
I have an AHS multi fuel boiler in my garage and I spent $280 all last year to heat my 3,500sq. ft. log home that is right on top of a cold mountain on the Md. Wv border.
http://www.vogelzang.com/NorsemanFurnaces.htm
http://www.meyermfg.com/woodchuck.html
http://www.englanderstoves.com
In case you are a novice, and we all were at one time. A woodstove just radiates heat. a hot air, or add on furnace blows the hot air through ductwork and into you house were you need the heat. And, of course, a boiler heats water to heat your house. No clue why the call an outside wood furnace a furnace. it is actually an outside boiler.