From a quick web search, it seems that your Asus G75VW has a mSATA slot, you may want to fill that, otherwise you'd have to replace your HDD.
I would doubt that a lappy would have a second HDD bay, but if it did, your ssd would work.
Q1: You should be looking at 500mb/s+ read, write speeds.
Q2: not sure
Q3: yes, easily. just from the "my computer" folder
The Samsung Pro is the industry leader, but any from Micron, Intel or OCZ will do.
any SSD -Solid State Drive (not SDD) will be faster than what you've ever seen from a HDD, so the numbers really don't mean a thing unless you have mission critical applications. Cloning can be done but is not recommended. You should install fresh to the SSD the OS, motherboard drivers (chipset, video, network, etc), then all windows updates, then all your programs.
1. The speed limit is not the ssd but the sata 2 connecter in your laptop.
2. It's not hard, just get some good coning software and fallow the directions. You can buy it or there's free one also.
3. You laptop can only fit one drive either the ssd or hhd. The hhd can be put into an enclosure and truned into a external hard drive.
My laptop has two ports for HDD or SDD. I have had two HDD plugged in and it just gave the over one a different drive letter. Acted like an external drive. So I plan on using the SDD as the main drive for the os and the old HDD for storage of movies, pictures, downloads and random stuff like that.
I'd recommend cloning your old HDD to your SSD. That way you have the necessary drivers to run your laptop. ASUS is probably OK, but with some brands you may find yourself missing a needed driver and have an awful time finding one.
My HP required extensive searching for an updated network driver. I finally found it on some eastern European company's site. It worked fine, but I can't help but fell I got lucky. HP was zero help.