One of the first things I would suggest you do is to take a refresher course. You'll brush up on your skills and re-establish your comfort level in the water.
Next, if you still have your gear, have it serviced and/or overhauled. One of the more knowledgeable folks can explain what happens to gear when it is stored for a long period of time.
If you need to rent or purchase your gear, take the time to research it. There have been lots of improvments made in the last few years, especially in computers, BC designs and fins.
And last but not least, welcome back to the fold. Diving can surely heal what ails ya! You'll get alot of good information on this forum, there's some good people here who are willing to share their experiences and lessons learned.