Can somone suggest me a good Helpful bike store?

If you buy online, don't expect the same sort of support that you will get buying locally, that low price has a cost. Your bike will arrive only partly embled, putting it together will be up to you. If you have problems, it may take time to resolve, you may have to send defective or broken parts back and wait to have them replaced, and you will have to reemble the bike with the new parts. Adjustments will have to be done by a local shop who may not be too happy about you buying your bike elsewhere. A local Giant dealer should be able to get you the bike you want, or if they are really helpful, find out from the distributor where you can find one. It might not even be possible to buy a Giant online, some bike makers try very hard to make sure their bikes are only sold by reputable retailers who service the bike after it has been sold.