Please take no offense here, I am honestly trying to offer the best advice to you that I can:
Don't do this yourself.
Putting up any kind of e-commerce site on your own, without knowing EXACTLY what you're getting into is a serious mistake. If you take credit cards, and fail to properly secure them against the vast multitudes of twits that are trying to break in and steal them is a major disservice to your customers.
I understand there are some ease-of-maintenance issues. If you decide to keep it at your home/office, you should hire the best consultant/VAR/integrator you can find. This is way beyond just "setting up a network at home and connecting it to the Internet."
There's lots of really smart folks here, and you're likely to get some great advice. The problem is that we can't see your setup, don't know all the details of your contract with the ISP, we don't know what you know and don't know. In short, there are so many variables, many of them CRITICAL to success and safety, that if you aren't sure about the configuration of the entire system, you need someone to see the site, review the ISP offerings, review your product or service, and make some very specific recommendations.
Getting information from a book may be helpful, but books are rarely absolutely current..they can't be because of the production lag.
IMHO, your best bet is hooking up with a VAR/Consultant....some ISPs have outside consulting services...shop around, get bids, get all the pitches...and follow-up on their references..take nothing for granted. With extremely rare exception...if it's not explicitly laid out on paper, it doesn't exist.
Good Luck
Scott