Yeah it sounds like it's time for a new catalogue. More powerful box will maybe allow you to push catalogue size a little further, but no matter what hardware you get, eventually you will hit the wall because the resource consumption can go up indefinitely as your catalogue grows.
I did a little bit of digging and in 2011 alone, I had a total of about 52,000 RAW files in my catalogue (I don't keep any JPEGs in there) , so about 13,000 per quarter roughly. At times, I found even this to be too much for comfortable work, but I'm too lazy to start a new catalogue each month.