First off how much protein are you having daily? What's your diet structure? When are you eating?

I always have shake post heavy workout. Supposedly the time immediately post workout is when your body can proccess the protein most efficiently.

What type of cardiovascular training are you doing? More aerobic than anerobic i'm guessing.

I loss a lot of muscle mass and fat while training for my races. Now I'm back to a regular lifting schedule and cardio activy more anerobic based. Lots of sprints and highly elxposive bursts of speed.

Look and the bodies of marathon runners vs. sprinters.

Learn to train your fast twitch muscles and you'll build more volume along with increased caloric intake.

As for your bench, that's completely independant of your diet (well not completely, but you get the drift)

Only way to get better at it is to keep working at it. Working with a spotter helps motivate you and keeps you pushing harder and harder.

If you plateau, switch to fly's using dumbells. You can always try eecentric or dynamic training where you overload (in your case 260-280) the bar and have a friend help you with the up motion. Concentrate on lowering the bar to your chest in a controlled manner.

Soon enough you'll be seeing gains.

Remember fast -twitch for more weight.

Jay 5'9 195
current max bench 345
current max curl (dumbell single arm 95)
15% b/f

I lift maybe 2x's a week.

(I used to work at UPS too)