f9q800 engine compatibility

Hi all. Can you tell me if there are any other engines compatible with my 2003 Megane 1.9 Dci.

My Renault dealer informed me I have the f9q800 engine, with f9a stamped on the rear, but I`m unable to find one in my price range.

I`ve asked a few ebay sellers if the f9q812 will fit, but I`m getting mixed responses.

Thanks.