I want to upgrade my lens...

But I am still a little unsure of what direction to go. If I understand correctly, the lower the f number on the lens, the quicker it is? I am thinking of getting the Canon EF 70-200MM F/4.0 L USM LENS , I will be shooting mostly Surf, and Moto-X with it. I have the Canon 75-300f4-5.6 III, but I so far am unhappy with the results of this lens. I get good shots with it, but I think they should be crisper than what I get out of it. Or do I just need to learn to use PS. At the moment I am using Jasc paint shop pro. Any and all help is much apreciated.

The F number relates to the size/speed of the aperture, so yes the lower the F number the faster the aperture it has. This helps in lower light situations, but if you think it means the lens will focus faster then no it wont. How fast a lens can focus depends on a couple of things but mostly the type and speed of it's focussing motors and the focal range of the lens.

The EF75-300 lens you have that your unhappy with has a fairly slow aperture and needs alot of light, it's also quite soft image wise and slow to focus but it's a consumer grade lens. If you want something faster focussing you need to look at a lens with USM or HSM etc.. depending on the brand.

The EF70-200L F4 is an ok lens but it maybe a little short in focal length for the type of shooting you do. Also do you shoot handheld or with a tripod as slight camera shake will make you images look softer also. I would think the EF100-400L or if the 300mm focal length is enough but your just after better images to look at the Sigma 100-300 f4 or maybe if you want a really fast aperture also look at the Sigma 120-300 f2.8 and both have HSM (Sigma's faster focussing system)

Canon's ef 100-400 IS would be a good choice
or
Sigma's 120-300 2.8, but that is pretty pricey

Your best value under 1k for distance in my mind is Sigma's 100-300 f/4.