How to increase the accuracy, f1-score and presicion for SVC in text classification?.

I have some text classification task with 5 classes this are the counts of each class:

5    1190
4     839
3     239
1     204
2     127

When I run a classification with SCV I have pretty bad accuracy, So I run a Grid search in order to find the best hyper parameters:

Best parameters set:
    clf__C: 0.1
    vect__max_df: 0.25
    vect__ngram_range: (1, 1)
    vect__use_idf: True

Accuracy:
0.456923076923

How can I increase the accuracy, f1 score and precision for SVC?