I have a tourist visa for China multiple 90 days valid for one year valid till October 29, 2012

I will travel to China and Hong Kong on October 27 with my other family members for 8 days. On November 2nd and 3rd we will visit Hong Kong and at the evening of November 3 we have booked a flight from Hong Kong to Chongqing where we have a connection with Finnair to Helsinki to return home. On my visa is written enter before 29. Can I travel to Hong Kong on the 2nd and return to Chongqing on the 3rd with this visa or not?
Can I apply for a new visa before this one is expired or not?