Breakfast, if you're a short walk from Bishopthorpe Road I'd go to Pig & Pastry for breakfast. If you're more central try The Rise at The Grand.
Most women love a trip to Betty's for afternoon tea, although you may prefer a pie in The House of Trembling Madness on Stonegate or a Pulled Pork Bun from Shambles kitchen.
Evening: Fine dining at The Park off Bootham. Skosh on Micklegate or for something a bit cheaper Gusto off Stonegate, Mediterranean try Delrio's next to Micklegate Bar, or Mumbai Louge for a good curry.