trying to start a business

Hello, my name Jim and I'm looking into starting my own screen printing business
(out of my home). I'm really trying to keep my cost down about how much do you guys think I will need to get started. I will just being doing t-shirts right now. I want at least a 4-color machine I have alot of experience. In screen printing doing cd's and dvd for my employer. My other questions how do you create the artwork for the shirts I know you use the computer but what software and do I have to hire an artist or graphic design person.

Thanks for All The Help

Jim