Sata controller in PCI-e 2.0 x1?

Hardware Hub Storage
1

At the moment I've only got sata-300 ports on my motherboard. I need a PCI-e controller because I want to upgrade my PC with the Samsung 840 EVO 250GB SSD.

Does a SATA-600 controller, in a PCI-e 2.0 x1 slot, work as fast as a normal sata-600 port on a motherboard? 

If not are there any other options? (Buying a new motherboard is not an option.)

edit:

PC specs:

CPU:                  intel core i5-3450 @ 3,3GHz (I overclocked it)

Graphics Card: Sapphire Radeon HD Dual-X OC7790 1 GB GDDR5

Memory:            6 GB RAM

Power Supply:   Corsair CX500M

Motherboard:    Gygabite GA-H61M-S1 (rev 2.1)

Storage:            1 TB HDD @ 7200 rpm

2

It depends on how good the controller is. Speed will be almost the same, only slightly slower. But the latency will be increased.

3

Do you have any recommendations below 40 US dollars or 30 Euros?