1) You can follow the same calendar according to that you had done your Mut'a first time.
If a man has a temporary wife whose ʿiddah has not yet finished, he can contract a permanent marriage with her or marry her again in a temporary marriage. However, if the period of the temporary marriage has not yet finished and he contracts a permanent marriage, the marriage contract is invalid unless he first gives her the remaining period and then contracts the permanent marriage.
So you can renew you Mut'a period for further dates once the first time slot has been over.
2) If her demand is as a dowry of Mut'a and you have agreed on it then you will be entitled to pay it to her.