We have a dedicated forum for SQL Monitor. You might want to post your queries here http://www.red-gate.com/messageboard/viewforum.php?f=133
Regarding monitoring frequency, though you can change via this config file RedGate.Response.Engine.Alerting.Base.Service.exe.settings.config which is located in C:\\Documents and Settings\\All Users\\Application Data\\Red Gate\\SQL Monitor 2 (or equivalent location) ... I wouldn't recommed it. These schedule have been set up with optimum results in mind for things like performance, data availability etc. Changing the schedule can affect alerts adversely.
Also, would be good to know though that why do you want to change it? Is there any specific problem you are facing?