need wifi connectivity for internet sharing with mobile and laptop

Hi
I have small house (4 room). I have 2 laptop and one smart phone. I need wifi connectivity for internet sharing with phone and laptop.
My internet connection from TD-8840T ADSL2+ Modem Router TD-8840T

Any 802.11n router would work, but how much do you want to spend on it?

Again, all you need for wireless is something like the following:

$20 - TP-LINK TL-WR841N Wireless N300 802.11b/g/n router

Shetu, I mean no offense when I say this, but based on your original post I get the feeling you may not have all the technical prowess to be able to set up a device like this. If you're currently leasing your modem from your ISP, call customer service and ask them if a 'Gateway' is available. A 'Gateway' is a combination of DSL modem and wireless router in one unit. Normally I don't recommend going this route, but it will place all of your potential connection issues squarely on the responsibility of your ISP.

For example, if you add your own router into the mix, if you have connectivity issues your ISP will probably be quick to blame the router, even though that may or may not be the issue.

Otherwise, tiraides is absolutely correct. Any 802.11n router will work perfectly for your situation, and I doubt if you would be able to tell the difference between a $20 router vs a $200 simultaneous dual-band high gain amplified antenna router.

Thanks @mhenley and @tiraides. I think it will be sufficient for my wife's cell phone.
please see this links if you have any alternative. If no then i make order tp link router 2nd june.

From that site, choose either the DIR-600L or the DIR-605L, both from D-Link. The DIR-605L reportedly covers a larger area.

I set my parents up with a Cisco E1200 when their old Linksys WRT-54G died, and can vouch for the reliability of that unit. Unfortunately, I haven't had any hands-on experience with D-Link products in a long while, only because local vendors don't sell them, but from what I remember they're solid products as well. For the price difference between the Cisco E1200 and tirades' recommendation of the DIR-600L or 605L, I will absolutely echo his recommendation and say go for either of the lower priced D-Link units.

On a side note: That site lists the Cisco E1200 at 5500 BDT, which converts to $70.83 USD. I can get that same model number from Amazon for $40.27 USD, or 3127 BDT. I don't know what options you have available to you, but I would shop around and make sure you get the best price.

I have to buy from local store (Bangladesh).

Did you get your links from your local store? If not, what does your local store have?

My local store (http://www.computersourcebd.com/)