You're not that bad off. you should apply then call schools and see if you need a retake. I was looking at the stats last night and most schools have an average DAT scores of 19, with around 3.5 to 3.6 GPA's. So you're not that bad off, you got 19 in bio, but the 18 in RC might hurt you. i would apply + call schools and then see what you can do. Whats your science gpa?
At this point you're still in the game, the question is have you submitted your app? if not then you might be in a bit of trouble since the application game is really heating up now that interviews are being scheduled.
ye man just hope to land some interviews and nail them out of the ballpark. not all hope is lost! I say if you have the time/resources re-take as soon as possible (i.e. after the 3 month window is over) if you dont have time or resources then apply and that you wont have to do the whole thing all over again next year.