Visa to Romania

Hi , I am Cambodian and i'm living in Phnom Penh, i want to get a Visa to ROMANIA for 5 months for studying. I have 2 questions on the visa process.
First, can i request for 5 months visa ?
Second, they require the medical insurance and i heard that they don't accept some of the insurance company so which company that they trust and willing to accept that insurance?

Perhaps contact the nearest Romanian Embassy for the information.

I live in Cambodia and the embassy is located in Hanoi Vietnam so it difficult for me to contact them.