I need some advice....

I have been promised a raise over a year ago that includes it to be retro to August 17th of 2006 but I have not received a raise nor have I been compensated the retro pay. What is the best way to approach my boss in reminding him of the promise? I do have a signed review which states the promise. I have thought about exchanging the retro pay for more vacation time which would help tremendously in getting my online store, Regalo Boutique, complete.

I just do not have the slightest clue on how to get what I am deserved. I know the company has suffered losses financially but during that extreme time period they have hired more plumbing technicians that make double of what I am paid and they recently have fired one. I am not asking for the world but only what I have been promised. Please guys I need your input.