Rejoice, rejoice, hallelujah.
Yep, that's an pci-e slot. It would have been a stupid mobo if it hadn't had one.
Now about that 5570 and psu ; you won't be able to get them both for 60 i think. But in spite of what i said earlier ( stupid me ) i think it will run on your 250W psu.
The 7750 would be a lot better and also possible on that psu but it's a bit more than 60 $.
If you wanne buy a new psu go for a good brand like Corsair, Antec, XFX, Seasonic. They cost around 50-60$.