The process involves adding "Add a Gadget" boxes to your existing template. Please see How to Add a Page Element (Gadget) to Blogger Header
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Rather than re-hashing the steps just follow the instructions in the linked post. This will allow you to add the necessary boxes for adding gadgets above the Post box as well as above the whole main wrapper and the header. See the image above.
Once you have added these boxes you can now add adsense (or anything else you like) above the post title by adding the adsense script in the box above the Post.
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I should mention that I never use the Blogger "Add Adsense" gadget. This does not allow you to use channels and is restricting. I always set up my ads in Google Adsense Set Up and then copy/paste the code directly into the "Add a Gadget" box on Blogger. Just select "add HTML/JavaScript" from the options - insert the Adsense code supplied by Google and you are done.
Cheers
Griz