Could not give us at least idea how much traffic is at your site at peak times?

Do you keep have server log, right?
Could not analyze server log (using an analyzer script or software) to see how much the traffic really is?

I mean something like: how many page hits/second are requested?
Even an approximate value would help a bit. E.g. less than 10 hits/sec, or more than 50 hits/sec...
(not that I know how much LSQL can handle, but I'm sure these traffic data can get us closer to the problem)

You may also look in the server log, which scripts are accessed the most times (a top 3 script list would be useful).