which bus should i take from Huaxiba...and how much would the complete expenditure?

Do you mean you want to go to Huanglong from Huaxiba?
No direct buses operate between the two places, so it is suggested to take bus to reach Jiuzhaigou first and then to Huanglong.
If you need, you can go to Xinnanmen Bus Station to take bus to reach Jiuzhaigou. The ticket price is around 141 RMB. Then take bus to reach Huanglong