how many bits does my macbook pro retina have

Macs are 64-bit. But you may wish to skip AV software. It's really not needed.

Helpful Links Regarding Malware Protection

An excellent link to read is Tom Reed's Mac Malware Guide.

Also, visit The XLab FAQs and read Detecting and avoiding malware and spyware.

See these Apple articles:

Mac OS X Snow Leopard and malware detection

OS X Lion- Protect your Mac from malware

OS X Mountain Lion- Protect your Mac from malware

About file quarantine in OS X

If you require anti-virus protection I recommend using ClamXav.

fleurdelis1101 wrote:

...if my Mac is 32 bit or 64 bit and I honestly have no idea.

How to tell if your Intel-based Mac has a 32-bit or 64-bit processor.