Getting in shape - it sucks

Wife signed me us for two 5K races in September. So I would like to go from overweight (215 lbs) couch potato to target weight (180 lbs) and be able to run the entire length. 

Here's my data so far. I'm going to stick with 4 miles until I can do that without stopping. I'm up to 0.75 miles - pitiful but improving. 

date	activity	distance	time	calories	portion run	first leg run	weight
27-Jul-14	run	3	NA	NA	0.4	0.25	NA
5-Aug-14	run	4	60	NA	0.5	0.5	NA
8-Aug-14	run	4	50	NA	0.6	0.75	NA