Te recomiendo la edición de Hamilton, Perry, and Michael.https://www.amazon.com/Poem-Cid-Language-Penguin-Classics/dp/0140444467/ref=sr_1_1?ie=UTF8&qid=1491786532&sr=8-1&keywords=hamilton+poem+cid
BTW "buscando ~~para~~": the for is "built in", like the at of mirar 'look at'
Personally I would recommend that you spend a modest amount of money to purchase this edition of the poem.