IPhone 4S - WiFi will only connect for a few seconds - HELP!

So this issue started just recently and I am not sure how to fix it.....

I have an IPhone 4S running the OS6 update.

When I first turn the phone on it connects to my home network for about 5 minutes. Once I start working on stuff (facebook, safari, messages, etc) then it changes from WiFi to 4G. I try to get back on my home network but it just searches and searches and searches and can't find my network.

If I turn it off and power the phone back on about 5 minutes later it's the same thing - WiFi is great for about 5-10 minutes till it's gone again.

There are lots of other items in my house that rely on WiFi all work great which is why I think it could be a IPhone issue:

IPad

Roku

Laptop

Wireless Blueray Player

For a week the WiFi was actually greyed out and you couldn't do anything but a hard reset fixed that but did not fix this issue.

I have reset my router from Comcast and my home internet router as well - no help.

I have already tried a complete reset/reboot of the phone and started at square one. It didn't help.

This stinks - makes my phone worthless for what I need it for.

HELP ME!