Fix Python – How to compute precision, recall, accuracy and f1-score for the multiclass case with scikit learn?

I’m working in a sentiment analysis problem the data looks like this:
label instances
5 1190
4 838
3 239
1 204
2 127

So my data is unbalanced since 1190 instances are labeled with 5. For the classification Im using scikit’s SVC. The problem is I do not know how to balance my data in the right way in order to….