Problem embedding if and or functions.

Row C in the attached file changes an occurance in row B of DE to DEA is the respective cell A is larger than 3021. This works ok, but I want to include an option if it find DEM in the Row B and change it to DEMA if cell A is greater than 3021. I know I can accomplish this with several more rows, but I just wanted to do it in one row. Any ideas.
Thank You.

Thank you so much for the help. Much appreciated.