I can guess the meaning of “今、生きよう” is “Live for the moment”. And, “生きようとも” mean “Let'ｓ live together” . “生きるとも” mean “I live too” . “生きるとも” imply an answer to “生きようとも”. It answers one's own question. This phrase emphasize “Liveing” by repeating “生きる” . It is verbal play

La frase significa "Ahora trato de vivir, voy a vivir y viviré." In this phrase , ”とも”　doesn't mean "together". It is the particle emphasizing the meaning of the verb " 生きる".