You'll be fine transferring from GRU to CGH at that time. I did the transfer a couple of weeks ago on a Sunday evening. I arrived at CGH at 5.40pm and was in GRU at 6.35pm. Bus journey took about 35mins. Cost was just over R$30. With a bit of luck you'll get the 6.30am bus, if not there's another at 7.00am.
http://www.emtu.sp.gov.br/linha/resu...numlinha=10350