At the moment, you do not need "anti-virus" for linux.
As you may have discovered, it is sometimes awkward to install software for linux (you will get better at it though: Use your distro's "Package manager").
This has the advantage that is is very painful for people to write viruses for linux: "Viruses" just do not work with linux because the multitude of linux distros all manage things completely differently. So they don't know where to install or how to set anything up. The "virus" probably doesn't have the permissions needed anyway
That's why we on LQ are always asking "What's your Distro?". All the configuration files are in different places, for different distros, unlike win
So, stop worrying. Use linux for the internet, and win for ... .. . whatever ( personally, I no longer see the need to use win for anything ).
If you are using linux as your mailserver, and forwarding email to your win computers (which I doubt is the case) then I think a linux-based virus-scanner-for-windows-applications might be a good idea. You can do some research on this.
Otherwise, I think you can just forget about "viruses" with linux.
The ideal solution:
Win PC for "games" (I do not play them) Etc.
Use the linux PC for anything
that connects to the internet.
Never let the win PC connect to the internet, and you'll be OK.