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 Shi-Da 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.