Had previously posted a few weeks back in beginners section but not much response (except from Sleepy Bear -Ta)
Anyway I have a half marathon in 3 weeks time and would appreciate a steer in the right direction

. I have only had approx 6 weeks training as I was out injured for 11 weeks prior.
I have worked my way back slowly! - I covered 75 miles in Feb, longest run in Feb was 9 miles at 9.32 M/M average pace, most other runs around 5-7 miles @ 9 M/M
Went out today and covered 11 miles @ average 9.40 but struggled badly over last two miles, steady pace turned into shuffle almost instantly at mile 9!!).
How can I maximise the last few weeks? - any thoughts on a intensive 3 week training plan - or is it all to late?
Ta