i am using AIS 5.0.0.594 …does i need any extra software for my pc protection just like spyware doctor for spyware malware bytes for malware?
You will find that most of us use various programs as backups or for second opinions.
In my signature below, you will note that I use malwarebytes antimalware (MBAM) and Spybot as my other programs.
Others here also use Superantispyware (SAS) and several other programs.
I agree with this statement. I like to layer my lines of defense for security, but doing it without causing conflict with other software. You can look at user’s Signatures here on the forum to get an idea of what people are using, search the forum for software conflicts, or post a question if you like.
Welcome to the forum. 
then what avast will do if i install extra protection like MBAM spywarebot?
Mbam works well together with avast…!
asyn
avast will be happy