I purchased ones at Carpet Right in Liffey Valley, they had a fair amount of selection and a few different standard sizes to choose from.
I know what you mean about huying rugs online, however I did have a look at the site and there are many nice ones.
If you're willing to make the trip there is also a fair selection in Ikea, you can have a look at their website to see if you see anything worth the drive!
Des Kelly on Longmile Road has a very good selection ranging from cheap and cheerful to decent enough quality.
I got a beautiful Jeff Banks Ports of Call Rug from Cleary's in Naas for a fair bit cheaper than the rug club or one of them had online. They had a fairly good selection of rugs too.
I was too at first, but I have to say I was very happy with the quality I received (delivery was free also) worth looking around the rug club website as they have a very comprehensive advanced search facility and they have an online chat facility to (I think the guys name is Brendan) and he will answer any queries/questions you have live online.