Perhaps using capital letters would help you get to D.III.
Also it would seem like you should be able to know your own options, and then let us tell you what we think about them, seeing as we don't know about your current money situation.
Here are some of your some simple options
Option 1: Stick to the strength of you team. It seems like you are an outside based team but when you played him you went with a inside attack and and 1-3-1 to combat his R&G and 3-2.
Option 2: Combat his R&G and 3-2 by using tactic that are good against them, but this time I would suggest a 3-2 because your inside guys are a little to weak to hold strong in a 1-3-1 formation. Also make sure to set your best defender against his best scorer.
Option 3: Seduce him and convince him to throw the playoff game.