So, what have you been doing with the notices that you've been receiving for the last several months? Lining the bird cage with them?
By the time that the IRS resorts to a Levy & Seizure Notice, it's largely too late to get religion and start doing much more than getting on a payment plan with them to pay off what you owe. With that much debt, you'll need to make full financial disclosure to the IRS and they will decide how much that you must pay per month. That's the ONLY way to stop the seizure now.
The fact that you're asking here what to do tells me that you have not been working with a CPA or EA. You need to do that NOW. You can't afford to not retain professional assistance at this point.