If you only need a place to crash over for the night, this flat is perfect for you. In the middle of Alfama district but not close to the streets most visited by tourist you'll have a quiet stay there.
If you also need more than this, Mafalda is really a welcoming person, fully ready to give you tips and make you some recommendations about where to go in her beautiful city.
What's left for you to decide is ... when exactly are you booking your flight to Lisbon.