10 mph for 30 minutes by february is a very aggressive goal, considering 10 mph for 6 minutes is a 6:00 mile and you're currently at 8:00. If you're two minutes off of the pace for 1/5 the time, getting there for 30 minutes is tough. Attainable, yes, but tough. In 3-4 weeks? Impossible.
In your position (no access to a track because it's too cold, etc), what I'd do is focus on bringing the mile time down to 6:00, which is 10 mph for 6 minutes (aka as fast as your treadmill will go). After that, work your way up in distances. Get to a mile and a half, then to two miles, then keep working your way up. I would not try to increase speed to gauge progress, simply because increasing 1 mph for 30 minutes is a much bigger jump than 2 or 3 extra minutes at 10 mph (which is a huge jump in itself). Don't count on your shape to improve that quickly is all I'm saying.
As for building speed, you can't really do it when the max is 10 mph, as you really can only build speed by sprinting, which should be closer to 13-15 mph. I would just work on endurance during the winter season tbh. You can work on speed on the track or road or field or whatever when the weather's nicer.
As it stands, 7.5 mph for 8 minutes is 8:00 for the mile. I would start from there and increase the speed in increments of .1 mph or so (without decreasing the amount of time until you hit a .0 or .5 unless you really feel like stopping 5 seconds early to "do a mile" rather than doing a little bit more, tbh it would probably help more to only decrease every so often). You should probably aim to increase by .2 mph every week, which would put you at 6:00 mile in 12.5 weeks, which should be plenty of time, even to drop two minutes. If you can go faster, do it by all means, because by the end of february, you'd be able to do around 6:53, which is still pretty slow compared to other high school soccer players. But don't try and push progress too fast. You're still dropping 2 minutes off your mile time in 3 months, which is very fast improvement.
This is, of course, coming from someone with very little experience aside from three years of running cross country/track and 2 years of "serious" soccer. I'm not a fitness trainer by any stretch of the imagination, so I don't really know all too well what I'm talking about, except that you can't push progress. My first year of track, I only dropped about a minute and a half off my mile time over the same time span (granted, it was slightly faster, so there was less room for improvement, but still), and that was after 3 months of hell.
tl;dr - don't push too hard