It is funny how I am selling my Indian stocks portfolio and buying stocks in USA using the ETF route and you want to bet on Indian rupee appreciating against the $.
If I was you I would not trade in currency but invest in Indian stocks that are mainly domestic consumption based and create a decent basket. Even better if you just start picking NIFTY ETF by Goldman Sachs or something on those lines where you wont have to pick individual stocks as it is time consuming.
I have been investing in NASDAQ 100 ETF by Motilal oswal (as I am bullish on USD) for the last year and a half and have seen decent returns. My point is that it pays to hold onto stocks instead of just plain currency as that would be pure speculation but holding stocks would mean your capital is used in value creation/addition and that would mean greater profits. It is a given that if INR appreciates the stock market is also going to be on fire and same goes for the USD which is why I am buying NASDAQ 100 so currency appreciation is complimented by rise in NASDAQ over time.