Hate to hear about a wreck... I hope you're ok. Parts can come from many different places. It all depends on what you are looking. Buellster and Pinwallcycle recycle used parts. You can websearch them by name or search ebay. Al at American Sportbike carries some things. And, of course there is the good ole local Harley Dealer. If your local Harley dealer has a good parts staff they can look up the parts you need and the prices are sometimes suprisingly low.
As for the specifics of a cowl mounting bracket... Is this what you mean?http://americansportbike.com/newdir/Item/17590
Good Luck.