Dwayne,
Not sure about where you can find a good instructor in your area, but check out the My TPI website for tips and drill.

http://www.mytpi.com

Keep yourself in shape, I swim - loosing speed is going to happen, not sure you can gain back young but be physically fit and that's all you can do

I've increased my average distance by 10-15 yards with every club by increasing my backswing rotation. It took 2 months of daily stretching and practice to change my swing but it was time well spent. I'm still conscience of making a bigger turn but the added distance is nice.

13 mph from 48-53 is not normal on age alone. Core strengthening and stretching (My TPI recommendation above) will help get some back.

It is an aging thing. As we get older mother nature takes its toll on our flexibility and thus our swing speed drops. You can start doing stretches using the TPI routines or any other flexibility exercises. I use a routine called The Foundation which builds strength in your back which is my greatest nemis. The other thing you can do is pay a small sum to a professional PGA certified fitter, and get more data than you would ever believe on your golf swing. One of the first things you are going to find out is what flex, kick point, etc., shaft you should be using to get the maximum distance from your current golf swing. Numbers do not lie. I got 19 pages of data from my last fitting. The fitter can recommend and let you hit different clubs and be open minded to different manufactures. I found out that my swing speed dropped a lot more than what I would have believed but with the proper shaft I gained back 15 - 20 yards more in my driver. Exercise and the proper shaft in your clubs will turn back the time of mother nature. Good luck.

Thanks guys for all the input, Went to a regional certified fitter last November will look into the TPI

It's all in how you are releasing the club through impact. Sure, the rotation and tempo are important, but the hands control the speed. Just as an example, my normal driver SS is around 110. I can give you 120 in a heartbeat, but it isn't pretty......lol