Buck-Upgrades depend on how "into" this you want to get and just the comment about sticking greens leads me to believe you're not going to be happy until you can. Therefore, your time is probably now. Some guys never upgrade and play quite well. Others can't get enough. In your case I'll bet 1 or 2 wedges would solve your sticking problem and maybe a driver to get you to where you can use them effectively. The Redwood putter is killer if yours doesn't fit the bill. You'll see what I mean when you start sticking shots.
Spin ratings on the clubs are important if you want to control the ball, the higher ones coming at the cost of the slow meter. The satin wedges are incredibly accurate but not too forgiving. There's a super reference put out by one of WGT's best. Search the forum for "club comparison."
This is a terrific game and only gets better as you upgrade, IMO. Start slow and you won't waste money trying clubs you don't know about. Look at what your opp has in his bag when you play-you'll learn a lot.
YJ