i would start with a nice clamping feedneck, maybe a trigger. but mainly play with your gun before you start upgrading alot. for your hopper and tank..it depends on what you are willing to spend. a 3k steely tank will get you started, but fiber tanks are light, if you have the cash. the halo b is a great hopper, if your on a low budget, check the B/S/T section for some used stuff.
Get a 68/4500 carbon fiber tank with high pressure, there is a WGP Stratos for 99 bucks here http://www.actionvillage.com/031-189-0003 and as for hopper I like the HALO B with Rip drive. Smart Parts Qlock feedneck should be your first upgrade though