Grep doesn't parse timestamps, and neither will your AWK script. You're going to need something more intelligent.
Some Linux distros came with a log viewer app that might be able to help, but I don't know what's available at the moment. I think the viewer may have been named something like "sawmill".
Failing that, you could write a perl or python script that parsed the dates and filtered lines. Or, for that matter, a
Java Application using the DateParser class. Probably doable in about 100 lines of Java.
AWK
might be able to handle the date parsing, too, but it would be a lot of work, I think.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.