Having sold two sites: the first a website and the second a company.
At your size its all about how much they want you ans how much you want them. Step into their shoes for a while and see what they see. Do they see a 10 million dollar a year business if they roll it out throught their sales channels? What value do they see? Position it from that angle. Don't fall for pe ratios or crap like that. Its one thing if you are a solid stable company w/ predictable revenues but you are not. Be polite but firm. Don't let them pressure you. If you need more time, tell them you are taking more time. They'll try to rush you.
Finally, as you are doing this, think HARD about involving some professionals. Lawyers to help you get favorable terms, tax ppl to help you understand the tax implications (there is a GAINORMOUS DIFFERENCE between long term capital gains and short term). I know its difficult since they cost an arm and a leg but you can me losing out on a lot if you don't get some advice. Reach out to you uncles cousins buddy. Everyone likes helping the young kid trying to fight the corporation. They'll give you some free advice esp if its a favor.
Don't be afraid to ask for help and advice! We live in a society. People will help you out.
Finally, if they really want you, they will be back, no matter what they say. Think hard if this is really what you guys want. But as hard as it is, also be stone cold and make some probabilistic calculations. I'm sure it is a passion, but its also a business transaction. The irrational guy loses.