I don't think that what has been suggested is viable anyway. 0% introductory rates apply to purchases, not cash advances as far as I know. I don't think you can pay off a loan by using your credit card, I would have thought you would have to withdraw cash and use this to repay the overdraft (I am open to correction on this). You should also bear in ming that cash advances generally attract interest from the time they are taken, i.e. there is no interest-free period.
If you withdrew cash on your credit card, repaid the overdraft, and then were able to transfer a balance to a new credit card and avail of a 0% rate on transfers, then it might work, but it's not something I would recommend, and seing as how you have just got a new credit card, I'm not sure you could do this.
As budapest says, you really should be looking at reducing your expenditure and thus reducing the overdraft.
The CU mightn't be a bad idea, but they may require savings before they will lend you money.