My laptop has windows vista and it came with windows firewall as well as ca firewall, I also just installed superantispyware. Will all this slow down computer and should I get rid of one of the firewalls?

Should use one firewall or the other, if you have CA firewall, just disable windows firewall (may lead to other issues in future if you are on a network or sharing files through a LAN) because windows firewall is more easily integrated into the OS for file sharing and networking and other or 3rd party firewalls may have to be manually configured for networking/sharing/LAN.

Is this just CA firewall or also the Antivirus?

Personally, I would suggest to get an antivirus software if you don't have one already and just use super-antispyware as a stand alone software (run it when you like) as opposed to letting super run all the time in the backround.

Really depends on your needs, post back