International Student obtaining work visa.

I am a student in Czech Republic from a third world country, and i am on a student visa currently. However student visa limits the number of working hours to 20. i would like to switch to a work visa, with my new job here, however i dont know much about the process. Keep in mind that i still want to study, just while being on a work visa. What advices would you give? Maybe someone has gone through the process as well. Thanks in advance