I797 expired but I94 & Visa is Valid

I’am in a situation as per below, please advice:

I797 expired March-26-2014

H1b Visa valid till- Nov-17-2014

I-94 valid till- SNov-17-2014

Is my stay is legal till Nov-17-2014?

Shall I do the H1 transfer at the above situation?

Do i need to file for visa extension before I 797 expires?

Please provide your valuable inputs.