The answer to this question is: "it depends." I would first suggest speaking with your neighbor about cleaning up the cement herself. Do this politely (it is your neighbor, and this is a long-term relationship (at least until someone moves)). If she refuses to clean up the spilled cement, you have three options.
Option one: clean it up yourself. I know that you did not cause this, but is the fight worth it? How much cement was spilled? If it was a small amount, take care of it yourself. If not, try another avenue.
You could submit it to your insurance company. Keep in mind that you will have deductible. Many insurance companies will simply pay out the the estimate minus the deductible. In this case, the entire amount of money needed to fix the problem is not available (given the reduction due to the removal of the deductible).
You could file a case against your neighbor in small claims court. This is not necessarily easy though. You may have to prove (as with most cases in small claims) that your neighbor acted negligently or intentionally. The technical definition of negligent regarding law is as follows: "If your property is harmed as a result of another person's conduct, and that person didn't act with reasonable care under the circumstances, you have a valid legal claim based on that person's negligence."
In a nutshell, she is responsible. She caused, either directly or indirectly, the spill of cement onto your property. The true matter lies in if she will take responsibility for the spill or not.