I saw that you have a sewing machine – its not hard to make your own coat. I made one for my previous beasties with fleece and wool. I made it with a high colar (for the backside of the neck) and an indentation for the tail and a big belly and chest band (I used snaps at first but then switched to velcro). It worked pretty good for our single digit temps (and the occasional below zero walks to the corner). My current beastie refuses to go out the door with a coat on, however. When the outside temps are below 10F she won't stay outside any longer than necessary to go potty - the squirrels can run around all they want then!
With respect to booties, mine will at least tolerate them when we go for walks but it's more for the road salt. However, the good pair I bought this year leak somehow (maybe through the stitching?) and she doesn't like them with they get wet inside. Nevertheless be sure you get the best you can find.
