Degree complement and using 那么 I came up with this sentence below.

她哭得那么多了

Is it possible to put 那么 after 得? 

多谢。
她哭得那么多了

You have misused the complement. We say:

她哭得那么伤心。
她哭得很厉害。

If you want to express she has cried many times, then you should say 她哭过很多次了.
So, your issue is 多了 isn't a correct complement for 哭. When you say 那么多了, you don't need 得. For example, we say 说(了)那么多了，we don't say 说得那么多了. 得 is just redundant here.