My question is I have 2 - 1 GB's of 1600MHz DDR3 Ram but can I have 2 - 1 GB's 1800MHz DDR3 Ram or I can't have different MHz of Ram because that will confuse my MB if I get one Ram I have to get the same right? Hopefully this make sense.

MY MOTHERBOARD CAN DO WITH RAM

4 DIMM Slots

Maximum Memory Supported: 8GB - 64bit

Memory Supported:
Non-ECC
Unbuffered
Dual Channel Supported
800MHz DDR3
1066MHz DDR3
1333MHz DDR3
1600MHz DDR3 (OverClocking)
1800MHz DDR3 (OverClocking)

If you're asking if you can add two 1 GB 1800 MHz. modules to the already existing 1600 MHz. modules for a total of 4 GB, the answer is maybe without knowing the motherboard. Some boards are fussy. Additionally operation tends to be the most stable when the modules match. Also, if you're configuring as dual channel and want to have one 1600 MHz. module and one 1800 MHz. module in each bank, that is even less likely to be stable or work at all. If you're intending to overclock, having matching modules throughout will probably yield the best results.