Why do you want to buy an obsolete, unsupported video card? Anyway, that card requires 20 watts of power, so 2 amps.
The recommended Minimum PSU for Total System Wattage using this AMD HD 6350 is a PSU of at least 400 watts.
You may find this interesting from PC Specs.com: http://www.pc-specs.com/gpu/AMD/HD_6000_Series/Radeon_HD_6350/449
Overall, the AMD Radeon HD 6350 has poor performance. This should be expected only from older dedicated graphics cards, so this graphics card should definitely be avoided if building a system to power modern applications and games. This graphics card is now over 7 years old, which means it is extremely out of date and is based on very aged technologies. The driver support for the AMD Radeon HD 6350 is now fairly poor, so don't count on any new game optimizations. You may also encounter more and more graphical oddities as newer games are released.
At this performance level you would be better off getting a CPU with an integrated GPU, because a dedicated graphics card like the AMD Radeon HD 6350 would not be worth the extra investment, and an integrated solution would be much cheaper, produce less heat, and require less power. We would recommend an Intel Iris GPU on one of the latest Intel Haswell processors, such as the Iris Pro Graphics 5200 Desktop, or one of AMD's latest APU Family graphics solutions such as the Radeon HD 8670D.
With an effective SPU count of 26, the AMD Radeon HD 6350 processes shading and special graphical effects fairly poorly. The GPU is not too power-hungry at 19 Watts, however.
If your Computer can use a newer AMD GPU card, That would be the best way to go rather than spending money on a card with no new drivers and not supported by AMD anymore. Plus it probably won't be able to play any of today's newer HD Games since the driver and the GPU card specs would be technically outdated.