Need Help!!

Guys I am pulling out my hair.

Can someone answer these questions:

I have a 60GB SSD drive that I want to put windows 7 and OSX on and dual boot, can that be done on the same HDD?

If not - Can I use an ESATA based external hard drive to do it?

Also for this dual boot scenario, I already have my Windows 7 installed on the 60GB drive - should I start over?