There is a decent store locally in Cedar Park, Buttercup Creek and 183
The Gun Store
Ignore the store pictures, they haven't updated their site from when they were in Houston
Another good store is a little further down 183, at Anderson Mill (NE corner)
Website is down, but I called, they are still in Business (512) 219-1122.
As for ranges, there's one just down the road. Good for normal range activity, and not busy during the week.
Eagle Peak / Leander, Tx
Also, there are two further north on 183, Stans and Astro (both are South of Briggs, TX)
If you're looking for indoor ranges, then it's Reds North or South.
Red's Indoor Range (North or South)
And finally, KR Training maintains a list of area clubs and ranges, check it out for more options.
Austin Area Guide to Shooting
Enjoy, and welcome to Cedar Park!