3g service has a good scope in countries like india. though the signal varys as per the locality, here's a tutorial made after being one of the victims to get regular GSM signal instead of a high speed 3g signal.

Step 1: What You Need

You need

1. Dish
2. 10 Feet Usb cable
3. Usb self powered Hub
4. A Long Stick
5. Screw driver, Few screws
6. plastic Gum Tape
7. plastic cover

Step 2: How It Works

If you are siting inside and dont get any 3g signal at all, dont worry i have a fix for you, im located in a low altitude area (3g blacked out, as per the service provider my area is under progress !! since 6 months for 3g plan) and 3 km away from the nearest 3g Tower.
I m using BSNL Huawei 3.6mbps modem and i use to get the regular GSM signal only which is not worth, but use to get the UMTS/HSDPA with a 1 single bar when i take the laptop out of my house witht he modem connected.
So i decided its worth to put the modem outside my house and have a usb extender connected(10 ft).
but if you are using more than a 5 feet usb cable your computer cannot supply enough power to it so you need to add a useb self powered hub to make the long usb cable active.

Step 3: Preparing the Dish !!! Yummy!

Take a a foot 2 feet longX1/2 inch width stick and cut one of its edge in a slanting direction so that there when you attach the dish to this stick the dish is facing up slightly. make 2 holes on the stick in a 45 degrees angle and put the dish and tighten the screws.

Step 4: Protect Your 3g Modem

I Have used a plastic cover to protect my 3g modem from bad weather and wind as show in the picture make sure the plastic cover you use is transparent and put the cover after you connect it to the usb cable

Step 5: Wrap It Up!!

Fix the preapared dish antenna to the highest spot that you can reach and you should know which direction is the nearest 3g tower located and face the dish towards it, even a small misalignment can cost you a 1 bar of signal. I found a spot by running around my house holding the dish. Finally fixed it next to outside my bedrooms secondary door.
Connect the the long usb cable to the Hub and hub to your computer. happy Browsing with good signal strength.