USB 3.0 PCI Express Cards

My ASUS motherboard does not have any USB 3.0 port for faster 3G internet connectivity via dongles though it has 12 USB 2.0 ports. It has three PCI Express and one PCI unused slots.
1. Can somebody guide me for reliable USB 3.0 PCI Express Cards available in India for ASUS F1A55-M LX PLUS motherboard supporting AMD A4 3400 APU 2.7GHz desktop computer?
2. As these USB 3.0 PCI Express Cards would be in the rear of the computer, I would need a multiport hub too to place in front of me on the computer table near my LED 18.5" Samsung monitor.
3. Would such a USB 3.0 PCI Express Card require extra power on would the current SMPS be sufficient.

I have 2 x 2GB DDR3 RAMs running my assembled 32-bit machine with SATA III 500GB HDD with operating system being Win 7 Ultimate SP1.

I had upgraded to this assembled PC in January 2012. My PC is not for gaming, TV, or other pastimes and is used basically for working from home on online platforms or via FTP as a medical transcriber.

I am no hardware geek, but would like to know if 4G LTE wireless internet connectivity would work with USB 3.0 or would there be need for a futuristic USB 3.1/4.0 which is backward compatible?