怎么用英文回复老外?写了一封开发信,老外有兴趣咨询,我给他回复后忘记与他联系,.现在再跟他联系了,他却回了这样的邮件.请

怎么用英文回复老外?
写了一封开发信,老外有兴趣咨询,我给他回复后忘记与他联系,.现在再跟他联系了,他却回了这样的邮件.请问该怎么回复比较得体,我是想说以后有机会可以跟我买,我会一直让你知道价格更新情况.还有说写什么好?
请用英文,
Subject:Auto fish feeder
To:export@kesai.com
Date:Sunday,December 12,2010,10:44 PM
Dear Kiki.
Thank you for your quotation about Auto fish feeder.I am sorry to inform you that,I already bought from Resun Company 45 days ago.Anyway thanks for your respond.
Paris
得体的英文回答追加分数!