waht kind of fertilizers?

That's a pretty general question Andy. Different plants have different needs.

Andy, check out the sticky at the top of the page. It will tell you the whats......then you can figure out the how much from there.
Len

N,P,K and Traces. How much of each will depend on plant load and to a large degree, your lighting. Iron on occasion if needed.
Excel is not needed when injecting CO2. CO2 is not generally needed in a small tank with moderate lighting. In that case you can use Excel.
Len

You have almost 3 watts/gal. It's really a tough call, but I would suggest CO2 injection for that much light. I don't think Excel will do it for you and especially in a heavily planted tank, it definitely won't be cost effective. For that matter, the other SeaChem products you mention will probably be pretty costly in the long run as well.
You could buy all of the Flourish products you mention and see how fast you use them up to determine cost effectiveness and then either re-purchase or go with the substitutes in the sticky at the top of the page. Or start looking around for those substitutes from the start. The Flourish stuff you mention is good and effective, but costly.
An Example: Not sure what a bottle of Flourish Phosphorous costs, but I bought a bottle of Fleets Enema at the pharmacy for a couple of bucks 5 months ago, and it'll probably last me a year!!!
Len

Funny story...

I asked my wife to pick up some Fleet enema at the store and she said, "awww, is your stomach feeling ok? Have you been constipated?"

No baby, it's for my fish tank... really.