I have this string:

" da licitação: r$ **43.470,00** (quarenta e três mil, quatrocentos e setenta reais)\n\n3 dos recursos orçamento são r$ **24.123,88**"

Note that there could be several money values in my strings. 
I want to separate only the largest, return should be "43.470,00" or 43,470.00 or 43470.

How could I do that?