I can't keep up with the cost of my medication?

My health insurance prescription plan reimburses me for up to $1000 (for example) per year. The drug (lets say "bottles of pills") my doctor prescribes is very expensive and he has increased the dosage to 4 bottles per treatment. I see him every 3 months for treatment. My insurance plan has enough money for 1 more bottle this year, which ends late June. Once the year restarts in July, I won't be able to afford the drugs after a couple treatments because I will have maxed out the $1000. The rest will be coming out of my own pocket. I am just a student with barely enough to get by financially. The remaining drug costs is enough for a vacation to the other side of the planet. Do you think I could ask my doc to write a prescription for just 1 bottle, before the year ends and use it for the next treatment? That way it'll offset the expenses for next year.