Can anyone guide me regarding getting a decent radio transmitter for quadcopter

Since you didnt mention your budget....
Go for a 6channel Tx if you are on a strict budget. Look for Flysky,Hobbyking 6ch radio. They are usually basic radios for a beginner. Costs less, works decently, but you will outgrow it quickly. Rs2000-3000/-

If you want something that is decent (good value for money and function) then go for Flysky TH9X or Turnigy 9X or 9XR. They are all 9 channel radios and can be modded further if you wish to, which would add lot of functions. You can upgrade to open source firmware, which increases the value of these radios. Rs5000-7000/-

If you can spend lil more check out FrSky Taranis X9D. They are same as the above stated 9ch tx but better quality with some additional features. Rs10000-15000/-

Just do a google search and you can find the reviews and comparisons.

If this is your first quad, then go for toy quads such as Hubsan or cheerson etc. They come along with a radio(its not a programmable radio) under Rs5000/- because bad piloting skills is a big reason why some ppl quit the hobby/flying. It also reduces damage when you get the real stuff.

Can u suggest some websites  for the toy quad as well as radio transmitters

For a 6channel radio http://rcbazaar.com/products/2011-avionic-rcb6i-24ghz-6ch-transmitter-with-receiver.aspx http://rcmumbai.com/index.php/product/flysky-t6/
for a 9channel http://rcmumbai.com/index.php/product/flysky-9x-2-4ghz-9ch-transmitter/

Most of the lhs'es are out of stock with toy quads. Cant find one, on the websites that I prefer. You will probably have to buy from international sellers or wait and keep an eye on the sale posts in this forum.

The list of lhs'es is big, check the link. Its a big list,take your time and search their websites or contact them. Let us know from where do you plan to get items, so that someone can comment on the seller/items, if any.

http://www.rcindia.org/rc-outlets-and-resellers/mega-list-of-all-rc-outlets-in-india/

for the Radio go on. rcmumbai.com,
for the toy quad visit. rcbazaar.com