Well, 10 miles now certainly puts you well on-course for 26.2 come April. You've got a few more weeks to establish a sound base before the 16 weeks begin. One recurrent theme throughout every programme is steady progression of the LSR with a lighter week every 4 weeks or so.
I'm sure some of the "more seasoned" folks out there will be able to dispense some suggestions for the final few weeks of your build-up before the programme begins. Shades seems to host a 3-4 runs/week marathon thread, could well be worth getting involved with.