Eat like you've never eaten before, boy! 
Seriously, that's the only way you'll get the mass. Don't bother
with the supps until you get true [u]professional[/b] and I don't
mean the salesperson at your local health and supplement shop. Most
of them have never trained or used the products before.
As you eat, continue working out, of course. Don't skim on the
carbos either. If you have the money to spend on a personal
trainer, look it up on the web.