ATI Radeon 3000 vs PCI-e x1 cards

I've been googling for like an hour now and all results on this I find focus on the size of the persons' pc case and not the power of the card so I thought I'd ask for myself on this forum...

The specs for my PC say my motherboard is called:

H-Apricot-RS780L-uATX (Apricot)

and that it only has:

Expansion Slots: 2 PCI Express x1 slots

In searching what this slot is used for I discovered there are graphics cards for this slot. What I'd like to know is if there is a card for this slot that is better than my integrated ATI Radeon 3000 graphics. I really think the only issue i need to overcome is the RAM but I think it's best to find out if there is a better card in case I do need to upgrade past my current graphics after I upgrade the RAM.

Edit:
Since I thought my RAM was fine till after I upgraded my processor from the single core that was holding me back now i know i need more RAM so I figure once i fix the RAM I'll notice the graphics is a problem but the RAM was holding me back from noticing.

This link tells you all the available upgrades for your motherboard. HP Pavilion Slimline s5600 Desktop PC series - HP and Compaq Desktop PCs - Motherboard Specifications, H-Apricot-RS780L-uATX (Apricot) - c02552467 - HP Business Support Center

This link shows you what GPUs are available for your setup. They will all perform better than your integrated graphics. Newegg.com - Computer Hardware, Video Cards & Video Devices, Desktop Graphics Cards, PCI Express x1