my 2006 iMac won't stay connected via Airport to my wireless network

I recently moved and am connecting my iMac (2006 Intel) via the internal Airport card to a high-speed cable network here at home.

For some reason, my connection started off fine but after a few hours (sometime minutes) of browsing the web, the connection will

slow to a crawl or just stop completly.

I've tried changing the DNS settings, turning Airport off/on, re-booting the wireless router (it's a Netgear) all to no avail.

The connection will seem to be okay and then...back to the molasses slow or no connection at all.

At my previous residence, I was connecting the same way without any issues.

Any one alse having this problem?

As an aside, there are 2 iPads, 2 iPhones and a MacBook Air all connecting to the same network without any issues whatsoever.

I would appreciate any insight or help with this problem. Thank you in advance!