Well, that really isn't an american IPA recipe, so you aren't going to get a lot of classic IPA flavor.
The generic American IPA recipe is something along the lines of 9ish lbs light lme, 0.5 to 1lb crystal, a big AA bittering hop, lots of flavoring hops, and several ounce of dry hop. IIPA's are similar, but have more LME and sometimes some sugar.
Amber malt is just light malt with some crystal, so you are probably using 5 times more than Stone does. They start with 2.25 oz of 16 AA ho - 3-4 times more bitter than you used. You don't have any dry hopping in your recipe, and that is what provides most of that hoppy aroma. Your finishing hops are also not one of the common american aroma hops. Stone's IPA's are finished and dry hopped with Centennial.
General American IPA rules - you want a highly fermentable wort with at most 1 lb of crystal. Use a "clean" american ale yeast. Pitch enough yeast to make sure they fully dry the beer out. Give it 2 weeks to ferment (or take FG readings) and then dryhop for a week.
Right- your recipe is not going to be a crisp hoppy beer. It's more of an English beer that is an odd recipe. I wouldn't expect much hops flavor at all in that recipe. It's not an IPA recipe like any that I've ever seen, so I'd suggest that the recipe is at fault here.
I'd skip the amber malt and the brown sugar for certain for almost all beer styles, and use only light (or extra light) malt extract.
I'd also suggest using the hops that "fit" a certain style until you get a feel for what you like in various beers. Using English and American hops in a recipe can work at times, but oftentimes just tastes sort of weird. Brown sugar is something that I never use, as I dislike the taste of fermented brown sugar (like non-sweet molasses).
For an American IPA, I'd do something much different, like the Stone Ruination recipe I posted (linked to above):
1 pound crystal 20 (steeped at 150-160 for 20 minutes)
Bring to a boil. Add:
4 pounds DME
Bring to a boil. When boiling start your timer at 60 minutes, and begin hopping: (Remember that you add the hops at the "time remaining" on the timer, so the 10 minute hops are added with 10 minutes left in the boil, while the one minute hops added one minute before turning off the flame):
1.75 oz Magnum [14.00 %] (60 min)
1.00 oz Centennial [9.60 %] (30 min)
1.00 oz Centennial [9.60 %] (10 min)
1.00 oz Centennial [9.60 %] (1 min)
4 pounds DME (added at flame out)
2.00 oz Centennial [9.60 %] (Dry Hop 7 days)
Use a clean well-attenuating ale yeast, like S05, at 65-68 degrees.
