Internet keeps dropping on I-Mac

Hi,

So recently, I moved apartments and had to get my internet connection re-established at my new place. Since then, the connection has been very intermittent, dropping out either once or twice a day, or sometimes even once every 3 minutes.

At the moment, I simply restart the wireless router (TP-LINK) and that seems to get the internet back up and running. However, it's not a permanent fix and thus becomes very frustrating.

What's interesting is that when the internet does drop, my I-phone 5S can still pick up internet through the same wireless connection with no problems. So makes me think there's an issue with it through my I-Mac.

I purchased my I-mac back in Sept 2011. I have the latest operating System (Yosemite?) with all updates installed.

Anyone have any advice or ideas for troubleshooting?