First thing: get a handle on your addiction issues yourself by seeking help outside the court and penal system.
You should also contact the revenue services division for your county right away to try to work out a payment arrangement. If you are flat broke, you can sometimes buy more time with the payments, but don't blow them off. Send whatever you can afford.
You CAN serve jail time to pay off the fine; how much exactly depends on the county. You'd probably be looking at a ballpark range of 10-17 days in County jail, but could get released earlier depending on jail conditions. But rather than looking to jail as the solution to your drug addiction, I would recommend you pursue other options: NA, for instance, or treatment at a nonprofit outpatient clinic. Call your local County Alcohol and Drug Department for a list of programs, or research them on the Internet. Getting a handle on your drug addiction will help you to fulfill the terms of your probation and to avoid another DUI in the future.
In the meantime, you can serve jail in lieu of fines, but you will need to get an attorney (or add yourself to the court calendar although that has risks given your drug use) to seek a modification of your probation.
Some judges will grant a stay on fines for a reasonable period if there is good cause (unemployment, illness, etc.). You can also respectfully request that the court allow you to perform community service in lieu of fines, which could easily be 130+ hours. I wish you luck.
I agree with what my colleague said in a general sense, however it is difficult to give detailed information without knowing what the underlying offense is. If you decide to go to an inpatient treatment program, talk to a lawyer about asking for custody credit (jail time credit) for inpatient drug treatment. It all depends on the underlying offense, your criminal record, and of course -- the judge.