Does your school allow you to take orgo I without Chem II? My school doesn't and I was under the impression that most schools follow that as a rule. If they don't, you may end up staying an extra year which might cost more than 7k for tuition. I can't advise you financially but that is something you should consider before you make any big decisions.
I would say that just taking 12 credits of Chem 2, OChem2, Bio2, is very doable. Especially if you know the Chem II material as you stated. However, this is coming from a die-hard Biology major. If you know you don't do well in science courses I wouldn't suggest taking that combination then. Three science courses can prove be harsh even for science majors. Also if you didn't like Orgo I, you will more likely than not loath Orgo II.