Quite interval in between watching the terminator and seen your post :) A bigger dish is always helpful but you shouldn't need it as of yet for what you require.
Did you input into the receiver you are using a Diseqc switch. Most Monoblock's have Hotbird as Port A and Astra as Port B. When first installing, have you set hotbird first and input to the receiver you are using port A of a Diseqc 1 switch and look for the signal, for Astra tell the receiver you are using Port B and you should be near enough.
Check the instructions with your Monoblock, some models have Hotbird as A and Astra as B, where some are the other way round.