Coldleft,
The specialist you would need to see is a vascular surgeon. He/she can usually do noninvasive tests of the arteries and veins in your extremities, to determine what is going on. In some cases, however, invasive testing may be needed.
Coolness in the extremities can be caused by several things. There could be a problem with the inflow (arteries) such as a narrowing due to cholesterol build up, a congenital narrowing, spasm of the artery, etc. If the problem is with outflow (veins), it could be caused by a clot or varicose veins. Some medical disorders, like diabetes, can reduce the flow to the extremities. There are psychological disorders which can cause a person to have cold extremities. Then, in some people, it is just the way they are, and there really isn't any problem.
If there is a problem, and depending upon what that is, treatment may be offered. Which may include such things as: medications, change in weight and/or activity level, arterial bypasses, vein stripping, stents, biofeedback, relaxation techniques, or even no treatment. But, again, a diagnosis would have to be determined before any treatment could even be discussed.
Hope you find out what is causing your problem. Good luck.