First of all, I may be confusing concepts from Heritrix 2 (which I use more) with Heritrix 1 (which I haven't used for quite a while). Sorry if I do.
The depth is a scope setting on the frontier. BroadScope would have a depth limiting setting. Or you can have scope with a DecidingScope.
As for what file types to download, I believe that should be set on the MirrorWriterProcessor you try to use to archive the crawled files (it is a sequence of DecideRules in 2.x).
By the way, wget / httrack are more easy to configure for this type of task, at least if you just need to have the most current copy of the webpage(s) in question.