I definitely agree on upgrading your PSU, even if it did have the correct connectors it may not have the correct amperage on the 12V rail which is used for the GPU, SSD/HDD and lots of other things.
For the price of the cards I would say go for the Sapphire card because in my personal opinion they are a superior manufacturer compared to MSI not that MSI are bad I just think Sapphire cards are more reliable.
That PSU will not be able to run any kind of video card that has an extra power connector. When you get one, make sure it is 80+ bronze rated at least, and make sure it is from a reliable manufacturer. Stay away from things like multiple 12V rails.
Also for AMD cards, Sapphire is the best manufacturer. For Nvidia, it's EVGA.