Yes, I think I am with Twpsyn on this.... The main way that you get better at Greek is by reading lots of Greek; and so, translation, whether into English or any other language, should be kept within limits and not be your primary study activity. Markos mentioned "cheating" by looking at a French translation; I don't agree that this counts as "cheating" or that it's harmful; if you've made an attempt to understand the sentence in Greek first, it's perfectly fine to check it against a translation. (In fact you should do this, if you're not certain about it. What do you gain by remaining in confusion?) But the key is that you should then go back to the Greek sentence and read it again several times with the correct meaning in mind.
I can see some value in studying Greek and a Spanish translation together if it helps you to get more insights on what the Greek is really saying. No translation in any language can convey all the nuances of the original, so there will probably be times when Spanish can say something more naturally, and closer to the original, than English can (and vice versa). It would also be helpful if you are planning to teach Greek in a Spanish-speaking environment someday. Likewise, if you are going into Classics, or Patristics, it would be helpful to study Latin translations of Greek texts, so you can learn the equivalences of words and constructions, and ask yourself why the translators made the choices they did. It can be useful to do these things in small doses, from time to time. But as a general principle, you will learn each language best if you focus on studying it separately.
Dic mihi, Damoeta, 'cuium pecus' anne Latinum?