If you are hoping to peak for the outdoor state meet in May, my advice would be to sort of "train through" indoor in order to focus on building a base during the winter/early spring. It sounds like you never really have ran solid consistent mileage and built up an aerobic base yet, which makes your 2:16 REALLY impressive. You don't have to do super high mileage, especially as an 800m runner, but getting in a good amount of aerobic running for an extended period of time will really help you improve your endurance, which should contribute to bringing your already very good 800 time down quite a bit more. I, for example, can run about a minute faster than you over 5k, but couldn't possibly come within 10sec. of your 800 time, so I'd say you have a ton of potential to go faster with improved endurance, even if you are more of a speed-oriented (i.e. 400/800) type person.
Over the next couple months, I'd work on gradually (emphasis on the gradually!) increasing your mileage, with mostly easy runs, but really running based on how you feel-faster on days you feel good, slower on those you don't. I'd start with about your typical mileage week from cross and add a few miles each week from there, taking a "down" week of decreased mileage whenever you feel like you need it but always working toward the end goal of increasing the miles. I don't know much about your background so I can't say what would be best for you to top out at, but just try it out and see what works for you I guess. Heck, for a young female 800 runner, it could be as low as 20-something mpw, but it could also be a lot higher, it just depends on you and what you can handle. No matter what, though, they key in my opinion is consistency.
Try to run on soft surfaces as much as possible, do strides several times a week to keep in touch with your speed, and after a few weeks maybe add in a weekly tempo run of 15-25min or some informal hill work (during base training I like to do hilly mid-length runs that I treat as sort of a "hill fartlek", with the hard segments of the fartlek being pushing the pace on the uphills). Weights a couple times a week would probably be beneficial (high weight, low reps), as well as core work. Toward the end of indoor you probably want to taper off the mileage a little for the bigger races, but until then I'd just treat it as a base phase. Outdoor then would be when you'd really start doing race-specific training, and that's a little more complicated. It would really be a lot better if you had a real coach. It's a shame that a 2:16 sophomore girl only has a football coach to work with!