I need help with SSL certs and Apache

moving site to a new server

[thrasher141]

I'm trying to figure out how to move my organization's website from server A (expensive hosting company) to server B (GoDaddy virtual dedicated server). I recently purchased server B, the GoDaddy virutal dedicated server and moved the site over. After a couple tweaks it worked fine! But I don't have SSL installed, and we accept donations (we're a non profit) with credit cards so I definitely need SSL installed. Right now, DNS is still pointing to server A. I'm needing some help with:

1) installing an SSL cert in Apache (Linux)
2) understanding certs and how to transition from server A to server B with little or no downtime in the site.

We purchased an SSL cert from GoDaddy that is currently installed on server A. Is it possible to install the same cert on server B? Does it first need to be uninstalled on server A? How does that work?

I'm brand new to Apache, so I'm a little over my head! Thanks for the help!