Can i have drive sentry and threat fire with my current antivirus?

Yes, you can. There are folks on Wilders Security Forums who run all of that and more, e.g.:

Avira free

COMODO Firewall Professional w D+

COMODO BOClean

DRIVESENTRY

ThreatFire

Sandboxie

Returnil

Personally, I stopped using any sort of real-time protection as soon as I discovered Sandboxie. I now simply browse safely with a sandboxed Firefox + NoScript and run potentially dangerous attachments and downloaded files in a sandbox. That's proven to be a bullet-proof method against malware infections, and just as pleasing, one that uses minimal system resources.

I scan e-mail attachment/files I download with Avira and Malwarebytes on demand for the sake of having a malware detection layer, but I could even do away with them anti-virus and anti-malware programs too if I wanted to.That's the beauty of sandboxing. You're working in a virtual environment, so if anything untoward happens, you just empty the sandbox and your system remains intact.