THE BRONX - Nearly six months after election day, state Sen. Gustavo Rivera (D-District 33) is moving into his new office on the Grand Concourse.Rivera says the foot traffic and public transportation make it a prime location to stay in touch with his constituents. "People will be able to access us, be able to walk in and just talk to our staff," he says. Local residents say they are happy to have their senator as a neighbor and they look forward to getting to know him better. "He's here to talk to us and we could express our feelings," says Bintou Darboe. Rivera says he will take the concerns of his constituents back to Albany and fight for the borough. The state senator will hold an official grand opening of his office next Wednesday from 5 p.m. until 8 p.m.Until now, Rivera had been working out of the offices of other local lawmakers.