Most WNC Library books can be borrowed for 3 weeks. Besides the titles listed below, here is a link to all of the library's Spanish grammar books.
A number of websites provide verb tables and exercises. A few are:
Spanish Verb Forms Prof. Fred Jehle has created a page with conjugations of the most common Spanish verbs plus related resources.
Spanish Verb Conjugations --a list of the most common Spanish verbs with full conjugations.
Study Spanish.com's verb lessons -- a guide with conjugations, drills and quizes organized by types of verbs.