For ministry and life, it is good to know Spanish
For Spanish conversation in Latin America, try audio CD-lessons 1-12 of Pimsleur's Latin American Spanish. See here on Amazon.
For learning conjugations of verbs, 501 Spanish Verbs comes with an audio CD to go with the book. See here on Amazon.
For Ecuadorian slang, I got the Kindle for $3.25 and found it easy to use. See here at Amazon.
A nice couple from Canada who lived in Ecuador are Dena and Bryan Haines. If you want to see what books and tools they used to learn Spanish on arrival in Ecuador, here is their page: http://gringosabroad.com/eleven-books-courses-we-used-to-learn-spanish/