Where can I find a longer bracket or how can I make one ?
A little clarification, please. It seems like you have blinds mounted outside the window casing, and I take it you want to add curtains, too, over the same window? What kind of rod do you want to use? What kind of curtains/drapes? If you'll do a search online for "curtain brackets with long projection", you see some options. (Sometimes the projection away from the wall is called "return".) Maybe that will give you some ideas.
Thank you so much ~ I really appreciate your help !
You're welcome. Good luck with your search.
When I had this problem what I used was and It may sound weird, but I mounted Plant Hangers and it worked wonderfully. Just a thought.
I just hung some like these yesterday for a client...they have an adjustable range.
How deep is your window casework?
Marilyn beat me to telling you the proper terms.
If you still can't find a rod with deep enough returns then you can making your own using plumbing supplies.
You can cut a block of wood and screw to the wall where it will be under your brackets. When we bought our house, the drapes in the master were done this way and we never noticed until we went to replace them.
I got mine at Wal-Mart. They are simple brackets. You can also use the fancier L-Brackets like used for wall shelves and simply flip them over.