I originally bought a 128mb monthly plan . I didn’t expect the site to be so popular but unfortunately the server keeps crashing and I can’t keep the site up. I just need to know how much ram will be needed for 1k+ hits a day running glype proxy on the VPS.

I have a drupal based site. The front page is about 200kb and I have 10 trimmed topics in front page. Currently the site is hosted on a shared server. My question is how many hits or page loads per hour/minute should I have before it would be necessary to switch to a dedicated server?
My host is hostgator.