can we fight a garnishment?

While I don't practice in your state, here is my take on it.

Yes, you will be paying this for a very long time. Bankruptcy doesn't normally cover money damages that grow out of illegal acts (your DWI conviction, etc.) and the garnishment is the only way they can collect their Judgment from you. Apparently, you owe them the money after a trial or a default Judgment was issued. Either way, you're basically on the hook for the money. There's no way out except trying to appeal to them on a humane basis, but after you injured them while intoxicated, don't expect much sympathy.

I agree with Mr. Robinson...your story would be perfect for a "don't drink and drive" infomercial, because it both highlights the risk of injury to others, and the potentially enormous consequences to the driver. You are in particularly unsympathetic position because not only did you injure someone while driving drunk, but you failed to carry insurance. That's a real double-whammy. You essentially violated two laws in causing injury to another. My recommendation is that you look for ways to "pay down" the debt...borrow money from the bank, from family, etc. Just because they have garnished your wages doesn't mean that you can only pay them that amount each month. Think of it this way...if you are paying 10% interest on the judgment, then every dollar you pay down the loan is like earning 10% on your "investment." It is an unfortunate situation, but it is one of your own making.