London

As informed on the earlier query you must fulfil admission requirements irrespective of your sister living in London. Not only must you have good grades, you must also meet IELTS score requirements of the universities and must take UKCAT.

Hi Vismay,
Your grades are decent, however you must also take UKCAT ( UK Clinical Aptitude Test) for admissions into a medical school in UK. Additionally you must take IELTS too. The only benefit you will be getting because your sister moved to London is that she will know the process. Your admissions into a college has nothing to do with your sister living in London. You must fulfill the admission requirements most importantly. Please read about UKCAT here
http://www.ukcat.ac.uk/ and visit university websites for admission information.
Good luck.

Hi Deepali,
Admission to LSE is extremely competitive. Entry requirements as per LSE website include a minimum of 70% in your bachelor degree or a CGPA of least 3.5 (out of 4) or above. Additionally you must take the IELTS or TOEFL. There is no GRE score requirement. The admission process is online. For better understanding please go through
http://www.lse.ac.uk/study/graduate/enquirer/entryRequirements/englishLanguage.aspx
http://www.lse.ac.uk/study/graduate/enquirer/howToApply/home.aspx
http://www.lse.ac.uk/economics/home.aspx
Hope it helped.

Dear yogi,
In my view if you are looking for better job opportunities then both the countries are good. However, if you are looking for PR then opt for Australia. Hope his helps!

Dear Dismay!
Apart from your 10th and 12th you need to clear the IELTS exam to apply to UK universities. Additionally, personal statement and recommendation letters from your school would be required for application procedure. Hope this helps!