For anyone who wishes to teach themselves Greek, I recommend:

The Basics of Biblical Greek by William Mounce
The Basics of Biblical Greek Workbook by William Mounce
(Work through these books slowly and memorize all paradigms and vocabulary words)

The Morphology of Biblical Greek by William Mounce
(This will help identify all those forms that the basic grammar book did not have time to cover)

Greek Grammar Beyond the Basics: An Exegetical Syntax by Daniel Wallace
(Work through this book slowly also and memorize all the categories and their defintions)

A Greek-English Lexicon of the New Testament and Other Early Christian Literature by Walter Bauer and Frederick Danker
(The standard scholarly lexicon)

Athenaze by Maurice Balm and Gilbert Lawall
(Another good reference grammar)

Novum Testamentum Graece by Nestle-Aland
(The standard Greek text of the NT)

Remember go slow and enjoy the process of learning. It will take awhile to get the grammar down, and it will take longer still to be able to translate with only the help of a lexicon. But that's ok, the fruits will be well worth the investment.