Total swim newbie, how do I manage 750 m?

Hi. I've never trained swimming before, and now I have to do a 750 meters swim (25 meters lane) in a triathlon competition. I can't crawl, so I will have to do with *** swimming. I'm not a good *** swimmer neither, so I expect to loose a ton of time to the other competitors. I'm not looking for any miracles, but is there anything I can do to minimize my time loss? Any easy tips to a total amateur in the last second (considering that I won't have any time to train before the event, this monday in two days)? Thanks! Andreas