Ok, I looked it up on google maps. The name of the street is 台北市大安區浦城街13巷. It’s one of the little streets that go off Shida Rd. behind the park. On the corner of this street there is a bar/restaurant that’s called 紅館. It is a red (who would’ve thought it 
) building that is completely open facing the park and has a balcony on the second floor. I think if you pass by Starbucks walking toward Heping Rd. it’s the next street to the left.
There should be about five Indian restaurants in this street but I haven’t tried them all. I like the Tibetan place and one other restaurant. Can’t remember the name though. I’ll check the next time I’m around. Prices can vary a bit but should all be around 150 NT for a veggie set meal.
If you really wanna treat yourself to something special and are willing to spend a bit more I can not recommend Saffron enough. It’s in Tianmu and they serve the best Indian food I`ve ever had! (Never been to India though)
Last time I’ve been there was in spring 2010 (I’ve been out of the country for a while) but I plan on paying them another visit soon.
Check http://hungryintaipei.blogspot.com/2009/10/indian-i-strongly-recommend-saffron.html for details, pictures and a review.
Everytime I went there the service was extraordinary (even compared to Western European standards) and they also have a wide selection of wines (which I never tried). The staff there sure know what they are doing.
And the Indian bread they serve is to die for.