Calculating time

Hello,

I'm creating a web application to manage information from an Online Racing League and am currently having an issue tracking time. I'd like to have lap time data of the various races then be able make calculations against that data to get "Top 5 Lap Times" or position the grid based on lap times etc. I currently have the time entered in a single text field in the format of M:SS.SS so for example 2:12.234 (2 minutes and 12.234 seconds). THis works fine for sorting but I cannot use it in calculations and it is not a valid Number or Decimal format. I think I need a TIME field which I don't see available. Why isn't the DATE & TIME field an actual time format?