Going for 21k in May 2011

[TheEd]

it sounds as though you have had the correct size recommendation and now you should check that maybe your feet have been slipping forward and so your toes are banging against the front

you becoming a runner with this happening

this shouldn't happen so much in winter as the feet do not swell

this is not so uncommon

see here - footcare
http://www.time-to-run.com/women/footcare.htm

don't worry too much about the title but look to see if there is anything there that can assist you

congrats

TheEd