In my post titled Preparing to go to Israel I gave a brief overview on how to obtain a student visa before you come to Israel. The student visa you get in the States will be good for one year and then you will have to renew it. I just renewed my visa this past Thursday.
About a month before your visa expires you need to go to the Ministry of the Interior and make an appointment. They do have a phone number but you will get an appointment faster if you go in person. Your appointment will typically be one week before you visa expires. If for some reason they give you an appointment that is after the date your visa expires you will need to carry the appointment slip and your passport with you at all times.
To get your visa renewed you will need the following items: your passport, a passport photo,money for the visa(bring exact change),your transcripts,letter from the Vice Provost, your financial report from school,your rental agreement, and proof you can support yourself financially. I did not give the price of the visa because it is subject to change. The school told me one price but when I went to get my visa the price had gone up by 20 NIS. When you make your appointment they assign you to a booth/cubicle number. Each person that runs these booths is different so they might request some or all of the above documents listed.
The visa I received on Thursday is only good until the end of September, then I will have to go and get another visa. I've been told this is because Israel is trying to crack down on foreign workers. Apparently some people get into Israel on a student visa, sign up for classes and then disappear into the country. This is why you have to give them a copy of your transcripts to prove that you have actually been attending classes. At the end of September you will have paid for and registered for fall classes and that will tell them you are a serious student. I'm not sure how long the visa I get in September will last.
I hope this brief overview of renewing your student visa was helpful.