One piece of advice from me, Don't upgrade to Windows 8. It's a complete pain in the ass. It becomes really slow after a few days and the only thing it's good at is helping you develop patience. And the UEFI boot system could cause problems if you have plans to dual boot Linux with it.
If you could increase your budget by a 100$ then you could get a pretty decent new laptop (Lenovo S Series) Otherwise it would be much better to go down the second hand route.