How to select suitable Ram for my machine

How to select suitable Ram for my machine

I have co i3 machine. Therefore, I know suitable ram is ddr3 ram. Is there
any othere factors that I need to consider when I buy a ram?
I have already installed 2 GB. here is the ram info.
RAM
Memory slots
Total memory slots 2
Used memory slots 1
Free memory slots 1
Memory
Type DDR3
Size 2048 MBytes
Channels # Single
DRAM Frequency 665.2 MHz
CAS# Latency (CL) 9 clocks
RAS# to CAS# Delay (tRCD) 9 clocks
RAS# Precharge (tRP) 9 clocks
Cycle Time (tRAS) 24 clocks
Command Rate (CR) 1T
Physical Memory
Memory Usage 50 %
Total Physical 1.91 GB
Available Physical 972 MB
Total Virtual 3.85 GB
Available Virtual 2.45 GB
SPD
Number Of SPD Modules 1
Slot #1
Type DDR3
Size 2048 MBytes
Manufacturer Unknown
Max Bandwidth PC3-10700 (667 MHz)
Part Number RMB2GB484CA4-13HC
Week/year 19 / 11
SPD Ext. EPP
JEDEC #4
Frequency 685.7 MHz
CAS# Latency 9.0
RAS# To CAS# 9
RAS# Precharge 9
tRAS 25
tRC 34
Voltage 1.500 V
JEDEC #3
Frequency 609.5 MHz
CAS# Latency 8.0
RAS# To CAS# 8
RAS# Precharge 8
tRAS 22
tRC 30
Voltage 1.500 V
JEDEC #2
Frequency 533.3 MHz
CAS# Latency 7.0
RAS# To CAS# 7
RAS# Precharge 7
tRAS 20
tRC 27
Voltage 1.500 V
JEDEC #1
Frequency 457.1 MHz
CAS# Latency 6.0
RAS# To CAS# 6
RAS# Precharge 6
tRAS 17
tRC 23
Voltage 1.500 V
Here is the motherboard info
Motherboard
Manufacturer Intel Corporation
Model DH61WW (LGA1155 CPU 1)
Chipset Vendor Intel
Chipset Model Sandy Bridge
Chipset Revision 09
Southbridge Vendor Intel
Southbridge Model H61
Southbridge Revision B3
System Temperature 40 °C
BIOS
Brand Intel Corp.
Version BEH6110H.86A.0020.2011.0218.1538
Date 2/18/2011
Voltage
CPU CORE 0.960 V
MEMORY CONTROLLER 1.104 V
AVCC 3.440 V
3VCC 3.440 V
VIN4 1.048 V
VIN5 1.056 V
VIN6 1.056 V
PCI Data
Slot PCI
Slot Type PCI
Slot Usage Available
Bus Width Unknown
Slot Designation PCIe x16 Slot
Slot Number 0
Slot PCI
Slot Type PCI
Slot Usage Available
Bus Width 32 bit
Slot Designation PCI Slot
Slot Number 1
Slot PCI
Slot Type PCI
Slot Usage Available
Bus Width Unknown
Slot Designation PCIe x1 Slot
Slot Number 2
I want to upgrade my Ram for better performance. If I add a ram for the
rest of the empty socket, what is the suitable Ram? This is for my
personal work. I use this for developments and gaming.