Complex sentence: After returning to Roma, he signed a new contract which last until 30 June 2012, and would earned a gross annual salary of €0.6M in the first 2 seasons, then increased to €0.7M and €0.9M.
Split into simpler sentences: After returning to Roma, he signed a new contract which will last until 30 June 2012. As a part of it, he earned a gross annual salary of €0.6M in the first 2 seasons, which then increased to €0.7M and €0.9M.