minutes and seconds in database

I understand that everything is sorted in the table under submit_time, form_name, field_name, field_value, field_order.. but what am I to do if I am using contact form 7 to capture both text and time (mm:ss)? This both end up in field_value and I can’t set different filed types. So everything is shown as a string which is fine except with wanting to list the time in ASC or DESC order… 11:23 gets listed ahead of 2:11 as the first number is smaller.

also, my submit time is showing as a unix number in my table

Is there a fix to this? Thanks so much!

http://wordpress.org/extend/plugins/contact-form-7-to-database-extension/