We visited Australia in October, 2011 and explored Melbourne, Gold Coast, Cairns and Sydney. If you are flying from Mumbai, Qatar Airways is a good choice with flights to Melbourne and Sydney. Jet Star is a good choice for your inter-city flights inside Australia. This article covers our stay in Gold Coast and will help you plan your itinerary if you are looking at a three to five day visit.
How many days do you really need in Gold Coast? If you plan on covering the theme parks, you will need full days in all parks (Sea World, Dream World) so plan to include extra days here. Otherwise, three to five days should be good enough. If you are short on time and need to cover the most you can, then base yourself in the Surfers Paradise area.
Where to stay?"Mantra Legends" is a good choice for your hotel stay. Its proximity next to the beach, shops, restaurants and bus stop makes it a top choice for travelers. Explore the beaches "Surfers Paradise" (look out for the Meter Maids :-), "Burleigh Heads", "Main Beach", etc.
What to do?Plan a day trip to explore the islands. McLarens Landing in South Stradbroke is an island resort with plenty of island activities. Personally, I feel North Stradbroke (an hour from Brisbane) is a better bet as you will find gorgeous white sandy beaches where you can sand board, or perhaps kayak off Amity point if you prefer.
Another must do activity is to learn how to surf. There are many schools/coaches who teach private or group surf lessons. I guarantee you this is a super fun activity and the experience is one you will never forget.