Running schedule to consistant 1 1/2 miles?

I got my Navy Diver contract about 3 weeks ago, and I have a physical screening test I have to p every month to keep my contract until I leave March 7th. I have one in about 3 weeks. It's a swim, pushups, situps, pullups, and then a 1 1/2 mile run. I ped it last time easily, but the run destroys me. I'm not a runner, I'm a biker&swimmer so I'm trying to get into running shape. I did it last time, the run, after the swim and everything else in 11:06. I have to make it by 12:45. Any tips on how to make it a bearable run rather than hell? I threw up afterwards and felt like death. Thanks from any veteran runners!