She says she'll email out the pattern at no charge. I'd definitely request the pattern (and really consider making the requested donation to a charity because patterns are rarely free).
I think you'll probably have to calculate each type of square/rectangle individually. Here's a calculator I've found helpful:
http://vrya.net/quilt/flash/QuiltCalc_Loader.html
I would probably put in 42"W fabric to be safe unless you know for sure what the width is for what you're buying. Plenty of fabrics are 44W and some are 45 (especially non-quilting fabrics), but you never know until you check the bolt. You can also calculate the fabric needed for the border (make sure to check the appropriate box for "finished dimensions" or "cut dimensions" -- I usually measure my actual quilt & then use "cut dimensions").
For backing: If you are sending it out to be quilted -- not a bad idea if all you have is a standard domestic sewing machine -- make sure to add in the extra inches your long-armer needs. I know one of my LQS quilters asks for an extra 4" and another asks for an extra 5". You may need to piece your backing unless you plan to order extra-wide fabric on-line.
I'm not sure whether you are planning to do bias binding (really nice because it has more give, but also more expensive and wasteful of fabric) or straight-of-grain binding. For straight-of-grain, I'd probably go with 1 yard of fabric for your binding, but here's a calculator:
http://www.lilystreetquilts.com/lilystreet/calculators I'm not sure if the calculator leaves the extra tail fabric for joining the 2 ends of the binding together. You need at least 12" for that, 20" is even better.
Good luck with everything! Sounds like a lot of fun!!!!!
PS -- You may want to consider investing in a rotary cutter. It can cut through both layers of the jeans at once ... makes the cutting go much faster and is easy on the hands.