Andy,
first off, great job on loosing the weight. Not many even make it that far. you should be proud of yourself.
Now im going to just address only what I know, or think I can help with theres no point in my trying to cover something i know nothing about.
http://forum.bodybuilding.com/showthread.php?t=272067 This is a great thread talking about pre and post nutrition in regards to the workout. Nutrition is so huge, and Protien especially for the guy going to the gym. With out protien your muscles have little chance to rebuild themselves, you'll end up doing more harm than good.
A good rule of thumb for protien intake... You should get a minimum of 1 gram of protien per pound of body weight. If your lifting it should be more around 1.5g to 2g of protien / lbs.
Whey protien in the form of a shake is good before and after the workout. It gets into your body quickly when your muscles need it most. You can get more details on that and what other sources of food you need with the above link.
Because our body compositions change over the years, and our needs are different, I wouldnt be able to suggest anything else as far as suplements. Perhaps someone else more educated could do that.
I personally dont take anything other than my protien powder. I eat whole foods on a pretty strict diet ouside of my pre and post workout shakes.
The more muscle your able to put on, the more fat youll be burning in the course of a day. As long as it works into your fitness plan I dont see how Cardio would ever be a bad thing. You certianly dont want to over do it, but getting your heart rate up and maintaining it for 10, 20, 30 minutes can only help. Especially since it looks like your doing cardio on a seperate day.
Hope some of this helps for you.