Sounds somewhat familiar.
Might I make a few suggestions, a grain of salt might be a good side dish.
1. Make yourself more available to the kids.
You have stated that you work AND go to school full time. Right now your children need you more than ever. Cut back where you can and understand that you cannot get this time with your kids back, so don't spend it away from them when the need you most.
Whatever your reasoning for being away, right now your kids probably won't see it the same way. It will be really easy for them to feel abandoned by both parents if you do. Your kids need your strength, and a stabile environment.
2. Don't worry about dating for awhile.
Any time spent away from your children right now could be a mistake. Bringing new women in and out of their lives will confuse them(and possibly yourself) further.
You have already stated you have a full schedule, adding a new mate too soon will only distance yourself from your kids further, while taking away from their stability.
It is very important that your kids understand that THEY are YOUR priority.
Think you want sex though? Study STD/HIV on the web for awhile, your drive will go down some..
3. One day at a time.
Sure plan ahead for things that matter, but focusing on what needs to be done now might give you a little sanity. Don't let the possiblities of the future bog you down today, you have too much to do.
4. Never ever talk bad about your childrens Mother to them.
She may be the scummiest piece of shit on the planet, but you don't need to be the one to enlighten them. They will know these things in time, and possibly be able to handle it better. The kids will take your negative comments personally as she is still their Momma,to them. This could drive a wedge between you and your kids, and again, right now, your kids need you more than ever.
Anyway, these things were just at the top of my head. You probably understand alot or disagree with some. I hope a little of it is helpful.
About the divorce, do it right, especially since you plan on moving out of state soon.. too many details can go wrong if you just throw something together.
Stay strong, your work has just begun.