"...a grey marble tablet marks the spot, inscribed with her name, and the word, "Resurgam." (pg. 83)
Resurgam means "I shall rise again" in Latin. This is an appropriate epitaph for Helen because her entire life, or at least the snippet of her life that the reader sees, was spent trying to better herself in the eyes of the Lord. Helen's good and honest life was cut short when she could have spent so many more years helping others and becoming an even better person. Bronte's use of a very biblical-type inscription for Helen's headstone again emphasizes Helen's religious characterization and how the other character of Jane Eyre saw her.
EDIT: In addition to showing Helen's pious characterization, the idea of Helen "returning" or "rising again" plays an important to the rest of the novel and Jane's life. The ideas that Jane learned from Helen's example while in school impact her decisions and actions throughout the rest of her life. In a way, every time Jane does something that she either learned from Helen or has does something with the influence of Helen hanging over her, it is al though she is risen again.