I roughly calculate you've got 3 1/2 months of training time before your race, and you're averaging about 9 to 12 miles per week.
I'd say if you keep all of your runs easy - no need to beast yourself - and increase one of your runs to a weekend long run; adding on about an extra 5 to 10 minutes of running per week, you will easily build up to 8 or 9 miles in training, which will be fine to run 10 miles with.
Maybe take a rest week every 3rd week, where you do maybe half of your previous weeks mileage and then the subsequent week add on another 10 minutes to the previous high mileage you built upto.
I'm sure there's a lot more experienced runners here who could advise better, but I would think it's easily achieveable based on what you're doing already, as long as you don't get injured. Just remember that all you need to do for now is base (easy) runs; this will prepare your body to stand upto the demands of heavier (speed/hills) training in the future.
Hope that helps.
Edited: 08/07/2012 at 01:22