After 3 days of backing up our commercial website from a shared hosting provider, choosing a new VPS provider, and doing all sorts of configurations in Linux to make our small website run a bit better in just 360mb of RAM, we're back online.
Actually, I don't think visitors noticed any technical problems in our website the past few weeks, since the problem with the previous host only occurs when logging in our website to administer it. But the past 3 days of tinkering have brought frequent downtime. (I'm very new to web server administration.) Hopefully, the current setup will work better now, and provide smoother usage of our site.
p.s. For the technically curious, the frequent downtime yesterday and today were due to thrashing, out of control memory and disk swapping, due to improper configuration of the Apache HTTP server under minimal RAM. Last night was a little better as the memory resources of Apache were minimized. This morning, I was able to setup nginx to work on top of Apache and reduce dependency on Apache.