Bank balance garnished from unemployment wages

My bank account was recently garnished for $140. I had less than that in the amount so now I have a negative balance. All of the money I've deposited for the past year has been from NJ unemployment benefits. I also have no real place of residence; as I was living with my parents until I was asked to leave. I've been moving here and there between family members. I do not have direct deposit; my benefit checks are mailed to me.
Here's my questions:
Can I cash my benefit checks and buy a pre-paid debit card without that being garnished so I can pay my cell-phone, gas, etc?
Can they take my car? There is no lean on it; it is paid for.