The best thing to do is rest it for a few days and return to running when you can walk on it without pain (it will get worse if you run on it) - you've got enough time but make sure ankle gets a rest (cycle instead to maintain fitness)
when you start running again try walk/running (2min walk/2min run) and build up - no pain then focus your attention on the HM in october
Be patient, you'll be fine
Andy
myrunningtips.com
Edited: 28/07/2012 at 23:20