Mike, it appears that your current stove is at best, barely big enough for your house, and you mention large single pane windows, which could really allow a lot of cold air in the house.
You need a bigger stove and better windows, pick your poi$on. If you really like your current stove, then fix the window/air infiltration/insulation issues first, let us help resolve the coaling issues, then get a new stove if those things still don't help enough. Throwing money at a new stove may not totally fix your issues, but I'm betting it will go quite a ways toward it on all but the coldest/windiest days.
I'm not sure why you are getting coaling up with ash firewood, my experience is that it burns down well, but I don't think perfect wood is going to make that stove keep your house warm when it is real cold, and the wind is blowing. There may be some issues that have not yet been identified, such as your draft being too strong, wood not as dry as you think it is, air leaks in the door gasket, maybe even running the air inlet on the stove too high, and letting all that hot air go up the chimney.
If you have a nearby Blaze King dealer, then they should be on top of your list. There are a lot of Blaze Kings in Alaska and Canada, so I think they would surely work well in Wisconsin. You would not be wasting time looking at them (cat stoves). You have not mentioned what size flue you have. If you have an 8 inch flue, I don't think the King would be out of the question for the size of space you are heating. If you are limited to a 6 inch flue, then the Sirocco 30 would be a great stove, and should be at the top of your list. Just because we sing the praises of the BK stoves being so good in the shoulder season for low and slow burning doesn't mean they don't work good when cold. They will heat well, but remember there is no magic, as heat demand gets higher, burn times will get shorter. BK stoves are good stoves, and will do what they say they will do.