A yougov poll for the Sunday times polled 1945 people May 9 & 10.

Overall 30% would vote to stay in on a referendum now while 45% would stay in un renegotiated terms

47% Would vote “out” now while 32% would vote “out” after re-negotiated terms

44% said they would like a referendum before the next election.

In other questions 61% of those polled said that the coalition government was managing the economy badly.

Full details of the poll can be found direct from yougov here.