what you are looking for just isn't possible with the current search engine. It simply works in measure of one, so search on older than 1 year, newer than 2 years, though you can search across all forums, rather than limiting it to one or a few.

It's worth persevering with for some searches, as google isn't great on anything older than a few months or a year, and won't find some threads from years back, as they are too far back in the history of the forums. So for old threads, the site search is the only option, and you just have to search back a year at a time, or in smaller chunks (more key words) if you get more than two hundred results.