First of all, you're right about not hiring an attorney. And you should be consulting with one right now instead of browsing blogs. Protective orders are VERY SERIOUS things in terms of the Texas Family Code.
Generally a protective order lasts either as long as it is stated to last in the order itself, but no more than 2 years, or for 2 years if no end date is stated in the order itself.
After the PO has been in place for a year, you may file a motion requesting that the court review the protective order and determine whether there is a continuing need
for the order. After a hearing on the motion, if the court finds there is a continuing need for the protective order, the PO will remain in effect until the date the order would expire under its terms or at the end of the second year, whichever is sooner. If the court finds there is no continuing need for the protective order, the court will issue an order that expires the PO on a new, earlier date.
Please hire an attorney.
You have answered this question yourself already. Your biggest mistake was not consulting with an attorney. GO talk to an attorney that handles family law. Many attorneys will give you a free consultation.
The maximum time that a protective order lasts is 2 years. Even if you had hired a lawyer to represent you at the hearing on the protective order, chances are that it would have been granted. (Most judges see the situation as one that if the requestor wants it, then there is no reason not to give it. They do not consider that the requestor may be using the situation to set the other person up for false allegations.)
There is really nothing you can do about the false allegations except to do your best to be in the presence of others most of the time and absolutely have zero contact with the requestor. If I were you, knowing that the requestor is making these false allegations, I would keep a diary of where I go & what I am doing - at least for a while until you can catch her in one of the lies. If you got to the movies, keep the stub. If you go to the grocery store, keep the receipt. I know this will be a pain but it may be able to alibi you sufficiently that the state would turn around and file false police report against her.