How crippling is an empty pocket to one's career?

I am a student, 23, at the national university who is to graduate end of next month, September, with a BSc (Honors) in Agriculture. I majored in Crop Science.

I was supposed to finish and graduate last year around the same time but due to financial constraints I was forced to defer my studies in 2011, by then i was in my 2nd year of study. Fortunately I got a financial donor, a family friend, who enabled me to resume my studies the following year, 2012, up to present, June this year.

Last month I applied at the same university and got accepted for masters in Tropical Entomology. And again, my shallow pockets let me down. My donor couldnt continue to fund me. The lectures are to commence this coming Monday, there is nothing I can do but to turn down the offer.

The unstable political and economic conditions prevailing in my country means less jobs for me to further my studies or at least help my poor and unemployed parents and siblings (young brother and two sisters). I am the first born in the family and they all are to look up to me, as the next( and sooner) bread winner.

Now my question guys is is there any assistance your country or organisation or friend can give to the underpriviledged but intelligent and hardworking (foreign) students like us to help achieve their life goals? What should WE do? My dream is to have a Doctorate (in bio-science related studies), and by that I will the be first in our family history to achive that , as all never reached tertiary level.
I come from the Southern Africa region.