i would say you could do 2 in a matter of 3 weeks.
i have a 5K on the 18th and an 8K on the 25th and i am worried, but i am gonna do it!! you should be fine!!!!
and yeah money on good shoes is money well spent. my kayano's i got about 3 weeks ago and man I LOVE THEM!!! next pair i am getting a pair of kensei's. i wish i could find them on ebay now, but they are too new... Asics is the brand in case anyone wanted to know.
as far as the pics go, i figured out after my first race to spot the photograhers...so i am ready for them now!! i'm a great actress!!
my first race in dec to now there is SO much difference in my body even i cant believe it. makes me keep going though!!!