What a perfect place to stay in Porto. You will be close to the river and to the Old City. The apartment will meet your every need, just be prepared for the stairs.
More importantly, you will never meet a better host than Lígia! She will share her knowledge of great restaurants and sites to see but she also shares her warmth and her sense of humor with you freely. She will also give you 4 rules for staying and the 4th is the most important.