I currently have a RB493G with two R52Hn cards with four omnidirectional swivel antennas installed.
The intended purpose of the unit is to function as a router and wireless access point for my home network.

What steps would I need to follow to configure the unit:
Single SSID
Provide 2.4 GHz wireless connectivity for G and possibly N standard
Provide 5.8 GHz wireless connectivity for A and N standard
Use both WPA PSK & WPA2 PSK authentication with aes ccm and tkip Ciphers

Should I be considering a third radio and another set of antennas to dedicate for the A wireless standard?

Please advise
Thank you

I think first step will be to read this http://wiki.mikrotik.com/wiki/Manual:TOC
You really don't need someone to tell you how to set just one ssid. You can see all the settings you want just connecting to your device.