Well if you have an eSATA RAID card that has a 1x connector it will work in any 1x slot or higher. You can also put it in a 4x and 16x slot if you wish. It won't snap it but it will work just fine.
If you have a RAID card with a 4x connector (common on larger RAID cards) then it can fit in a 4x slot or higher. If you're extremely careful you could even cut part of the connector off and fit it into the 1x slot. Don't do this though.
DVD+/-RW Drives (2) using IDE ATAPI
3.5” Serial ATA Hard Drives (4) using SATA ; Four Serial ATA interfaces support data transfer rates up to 3.0 Gb/s
Built-in ATI graphics processor
provided by the ATI Radeon Xpress 1150 chipset
First you have a (4) four onboard SATA connectors so you can have (3) three additional SATA drives connected. Next, you appear to have a x16 and x1 PCIe slot so IF you're using the 'Built-in ATI graphics' for your video (monitor) then ANY PCIe card can be installed in the x16 PCIe slot as long as you have adequate PSU power if a supplementary PCIe power is required (most PCIe SATA Cards don't).