Running Compound Sentence

Is the following sentence punctuated correctly? Should the semicolong be a comma, or should each independent clause be separated with a semicolon because if one is, they all should be? I used a semicolon on the last independent clause because it has internal commas.

I had to look all over Berlin, and the puppy cost me a small fortune; but for the girl I love, Monika, nothing is too much.