Is there a differences between Antivirus & AntiMalware?
Do I need both?

The simple answer:

A virus is software writen to spread itself and multiple just like a real virus does.
Malware simply means Malicious Software and includes popup ads, password stealers, etc. AND Viruses. Anything Malicious.

So do you need both? For the most part, No. Many anti malware programs or good antivirus programs are designed to do both. But there are some which are not.

Viruses typically get into your computer from a infected website, a link in a fake email that you click or an infected attachment you open.

While it would be nice if these programs we put on our computers protected us, the truth is they only block about 50% of the threats. You can ready more about what to do and not to do at this links:

Viruses & How we Get Them Today.

Why Antivirus Software No Longer Works

So to protect yourself we recommend a good Anti-Malware program since that will do the best job of blocking the front line when something tries to infect your computer.  Unfortunatly the big name Antivirus companies have made there software so bloated and big they often cause many other problems such as slowing your computer down or blocking so much youthat end up with problems printing, connecting to your network or server, etc.

 You can read more at http://lifehacker.com/the-difference-between-antivirus-and-anti-malware-and-1176942277