If you are searching for a place tot stay near centre of Porto, I can recommend the place of Aurora and Alberto.

The place is calm and lovely, has a very nice garden with you can use, a served breakfast every day, lovely, nice decorated room and even more lovely bathroom of your own. They have lots of tips what to visit in Porto and are alway wiling to help.

Porto centre is at walking distance, supermarket and postoffice too.
Near a metro/train station and bus to centre.

If you stay buy a massage for an even more relaxed holiday feeling after a day of exploring Porto......