https://community.newegg.com/eggxpert/computer_hardware/f/135081/t/45344.aspx
You should definitely pick a higher quality power supply - Antec, Seasonic, EVGA, and Corsair (excluding the CX-series) all make good units.
You won't be happy with an R7-240 - it's an entry level card, and you'll be playing at the lowest quality on the lowest resolution possible:
http://www.tomshardware.com/reviews/radeon-r7-240-and-250,3717-4.html
I'd consider dropping the Athlon and going with a Haswell-series Pentium and an inexpensive motherboard to match. Use that money to get an R7-250, or even better would be a 260 if possible, as the 250 is still an entry-level card.