Looking at the horoscope of your sister, Jupiter is the lord of 7th house of marriage and married life and well placed in the 9th house. Venus the karka of marriage is debilitated in the 4th house. There is no Manglik dosha as Moon is cojoined with Mars in the 7th house. However Matching of the horoscope should be done for marital happiness. Strong chances of marriage are before March 2015. Can be in the second half of 2014 as well. Doing the following remedies will help get desired results.
1. Read Hanauman Chalisa Daily.
2. Keep fast on Thursdays.