Yes the regulator is available at most auto parts stores and online. I found the following website and it's possible that your battery voltage is lower than it needs to be for the light to go out. As long as the alternator is charging you might try ignoring the light until the battery gets fully charged. You can't ignore the light wire, because the alternator won't charge without it connected.
Changing the regulator is fairly simple if you go slow and keep track of what you are doing at each step. The regulator is mounted on the rear case of the alternator and when you separate it the brushes will fall out . They fit into two little housings on the back case.I had a step by step teardown saved somewhere and I've been looking for it. If I find it I will post it up.
I don't know if this link will make sense to you but it may help.
http://www.alternatorparts.com/under...lternators.htm