To learn enough German to "get by" in a university-level German/English-reading, writing, and speaking environment in a short time I strongly recommend that you purchase a hardcover edition of P. F. Doring's "Colloquial German". Although the book is thorough, it most likely will not quickly get you to the language level you want to attain.
Doring's book is a German grammar book that I believe you should purchase to both amuse you and at the same time help you towards achieving your goal.
Doring's book was first printed in England in 1946 (very shortly after the end of WWII), and was originally titled "German for Adults", and retitled "Colloquial German" for the American market. It is a rare book, but the cost of offerings of the book via Amazon and its vendors is remarkably very, very low.
Doring's book is eminently readable because it's obvious from his text and the examples he used that he had an especially droll of humor, and that adult humor comes forth in the content of his text, exercises, and adult level of vocabulary that he uses. Sometimes the text of his reading examples would not stand a contemporary PC test and, it's obvious his context that Doring didn't write his book for conventional high school and college level study; he obviously wrote his book for adults.
A technique that Doring used in his book is several paragraphs of an incident (e.g., a flight by [1930's era] 'flugzeug' for a short stay at a hotel in Prague, dinner at a fancy hotel with his wife, etc.), then newspaper-style parallel columns for learning and easy translation of German-German and German-English questions and answers relating to the incident. In his hardcover book Doring includes witty irrelevant stories (Aesop's fable of a dying lion, other animals attacking him, and a horse that didn't, for one example). Also in the book you will find a short four-line word puzzle with the answer printed in inverted type below the puzzle.
I'm sorry that I'm not adept at describing Doring's book, but I have rather excitedly purchased three copies of his book for my library from Amazon and two Amazon vendors, including a very rare edition printed, as it says, "during 1946", the first year of publication. No edition of this rare and exceptional textbook has cost me more than a few dollars; the shipping cost alone has been more than the cost of the book! The book is pocket-book sized, and shipping costs are nominal.
You'll note that I have specified the hardcover edition(s) of Doring's book. This is because in 1975 the book was heavily edited and revised by Inge Hubmann-Uhlich to 'modernize it' by changing Doring's adult-oriented examples to high school and college level examples, and in doing so she rather seriously (in my estimation) diluted the author's humor and humorous examples and text. The last edition by Doring himself was printed in 1973.
Do not by any means be 'turned off' by Doring's book because the text context and examples are pre-WWII, 1930's era. Of special interest to you might be Doring's rather long list of German Public Notices (e.g., Stossen = "Push", Ziehen = "Pull" and "What the Teacher Says": Ubersetzen Sie = "Translate", War das richtig? = "Was that correct?"), expressions you might find useful as a Fullbright scholar.