Have your wingman hyper in first to the convoy, he is invuerable and can draw the fire of 1 of the A/S. THe other one you can take out (tho you wont be healthy afterwards) by having your shilds at 200% and lasers charged at full.
Just go head to head with the A/S with both lasers and Ions blazing, once he is tries to evade, hopfully you will be closer then .5km dead fire 2 proton torps at him, then finish him off (disabling helps)
next target the convoys that look like big chains. Destroy the engines and then the rest should be easy (one re-load is about all you have time for in the last mission)