I'm not sure which connector you're going to need (sounds like power pack for an electric flyer?), but your LHS should be able to help... does the end you need look like a servo connector?... If so, you could sacrifice a servo extension lead to get the connector you need..... just make sure when you cut the old connector off, that you cut one wire at a time.... the smoke from burning wire insulation when you short out the battery cutting both leads at once will almost certainly set off the smoke detector!(At least it set off mine!)