SAS drive replacement in Proliant server and compatible drives
Replace your existing disk first. The 146GB 2.5" SAS disks are no longer manufactured. Even HP sends 300GB disks as replacements for 146GB drives.
You're in Spain, so your best bet is to buy one or two replacement 146GB drives from eBay. They're very inexpensive.
The server you're using, an HP ProLiant ML350 G5, is very old. I would not recommend using SSDs in it. If you use SATA SSDs in particular, they will link at 1.5Gbps instead of 3Gbps or 6Gbps. You'll lose a lot of throughput performance if you do so.