As a female there are road bikes designed specced for the serious dame rider---Trek,Giant,Pinarello,Jamis have good bikes you may find----check your craigslist.org or Ebay.com (sporting goods-outdoor sports-CYCLING-road bikes )---
Please do find the time to check this particular triathlon bike I just saw on EBAY.com It is item no. 330398678518 - a GURU CRONO triathlon bike---it looks fantastic! (2007 model but it looks mint---)
Be sure to hydrate well with plenty of liquids! The sugar or glucose will definitely rise as you pedal---add some bananas to convert all the extra sugar while you ride and AFTER the race RELAX and cool off---
When I got the TREK 2009 MTB color catalog ( get 1 at your nearest dealer NOW) -I figured the REMEDY series were the ultimate. ( Others I find hard to resist - Norco Six, Bionicon SuperShuttle and Felt Redemption One ).
There are cool simple hardtail bikes at EBAY.com ( Kona,Trek,Giant etc.). Hardtails with front suspension have average weight of 23-35 lbs.-but can handle asphalt very well. ( in EBAY -go to Sporting Goods category and find CYCLiNG-Choose mountain bikes/Road bikes either brand new or mint...