New to Overclocking, Please Help!

2.8 is definately a realistic aim. I O/Ced my Athlon 300 by 0.6 Ghz, 1.8 to 2.4, using just the stock cooler and Corsair value RAM. You don't want to alter the Vcore until you have to, and it is best clocking it up in steps, adjusting voltages as you go, to reach stability.
I did it in partly in the BIOS, despite having the decent Abit desktop overclocking programs, as you can only alter RAM settings in the BIOS.
First thing you will want to do is enter the BIOS, then go to where you can alter the FSB, notch it up a bit, maybe 20mhz at a time, exit the bios and save, see if its stable. Then do the same until it crashes, if it does, lower the RAM speed, select 166 or lower, then try again, if it crashes increase the Vcore, and try again. This will not decrease RAM performance as it it increased relative to the FSB when you increase that. You should easily make 2.8 Ghz with that cooler. I would also reccomend running Prime 95 when you are happy with the overclock, to see if it is stable under load.

Well lowering the RAM speed in BIOS only lowers the ratio between its speed and the stock speed of the CPU, if you raise the speed of the CPUs FSB, then the RAMs speed increases too, and will probably end up being faster than it was to start with, so you won't lose any performance at all. You can check its operational speed with a program called CPUZ. If you didn't lower its ratio, it would end up running over its capable speed, and would become damaged, or at least not let the computer boot. I think the max Vcore I put into mine was 1.7v, which is not the most that my motherboard will allow. You probably won't end up frying your CPU with too much, but you want to use as little as possible, as the more volts, the more heat it will create, and the less stable your cpu will be.