I'd start out with a few eyeshadows, lipsticks, and a blush or two, plus a lipglass or 2, and or course a few brushes.
Eyeshadows, start with 2 neutrals and 2 brights. Lipsticks? I'd recommend trying a bunch, and choosing an everyday lipstick and a red one. Then, 2 lipglasses, an everyday and a bright. Blush, choose one which gives you a natural flush, then add on that. Brushes? Get a crease/blending one, a 213, a 239, a concealer brush (194 I believe), a brush for your foundation (187, or since you use MSF natural, 182)
Wow, that's more than I was expecting.
And don't feel pressured, you've got time! This is actually what I'm building up to. I now only have 2 lipglasses, hah.
Edit: An angle brush with an brow-colored shadow and a fluidline are good to have, too.