You may be aware that you need a bigger tower for a larger card but we need to know what type of case you have to make sure that any cards suggested will actually fit.
Before you spend cash on a new video card I suggest that you upgrade the PSU either first or at the same time, the present PSU is a poor quality and output brand, if you look at the Speccy results that you provided and the PSU tolerance table that I have attached below you will see that the +12V reading of the present PSU is only reading 9.235V so there is every chance that it will not provide enough clean and stable power for a new card or in a worse case scenario it may damage it.
Please note that there is one thing that is possibly worse than using a known poor quality brand of PSU and that is using one that is unheard of, for brands of PSU to trust and brands to avoid please refer to the two attached links http://www.10stripe....d/psu/brand.php
PSU database http://www.realhardt...vos/Page541.htm
Before purchasing a new PSU it is advisable that you measure the dimensions of the present PSU and ensure that the new PSU has the correct power connections for the MB, HDDs, optical drives, FDDs or add on cards such as a video card if one is fitted.
Quality brands include Antec, Corsair, OCZ and Seasonic.