Buying a mac is pointless for your intended uses, not to mention no software you currently have will run on it.
I would imagine you,ve had it with your 6 year old compaq, odds are it was old on sale tech when you bought it so the tech in it is probably 8-10 years old.
Any PC with 4G ram + 2.0+ dual core or better CPU, and a 7200 rpm drive will blow your mind. And since your willing to shell out $$$ for mac, get a PC with a SSD hard drive, and you will really be impressed