You already have one of her,and that what I considered

原文有误。应该是You already have one of hers,and that's what I considered。你已经得到一个她的（东西）了,而且这一点我考虑了。所有格代词直接作名词性句子成分时,应该用名词形式的所有格hers,而不是形容词形式的her。and是连词,后面跟的第二句少了谓语动词(is)。what I considered是这句的表语。