i'm wondering if i could use
MSE with avira or avast for extra protection
It is not recommended to run more than one antivirus program because if more than one have real-time protection enabled, it can cause issues on your computer. However, as long as you only have 1 real-time protection enabled, then you can use the others as a backup scanner, however there are better programs to use for that such as Malwarebytes' Anti-Malware and SUPERAntiSpyware.
if not
:/ what is a good HIPS
There are a few free HIPS programs out there. Here are two of them: