Question relating to "Spyware terminator", please answer this.?

I have an anti-virus installed in my computer and i installed Spyware terminator just now.After installation its giving me an option " How would you like to use this program ? 1) scan for spy wares , 2) protect against spy wares and 3) protect against viruses and spy wares. So, can i go for 3) protect against viruses and spy wares ? I'm confused because i already have an anti virus and if i make spy ware terminator to protect my computer from viruses also then will this be a conflict between an anti virus which is already installed in my computer and anti-spy ware which I'm installing "spy ware terminator?