Welcome to the forums!
Many of the newer ASUS G-series notebooks (like the GL502VS and others) still use a 180w adapter that would work for your G75VW notebook, so it shouldn't be too difficult to find although more models like the G750JH, G750JZ, G751JY/JT, G752VY, and G752VS are using the 230w adapter that will not work for your G75VW notebook, so you still need to be a little careful.
Although the design of the newer ASUS 180w adapter 'brick' has changed some (it's slimmer and more compact than the original 180w adapter that came with the G75VW), it still uses the same plug size and will work for the G75VW.
Anyway, hopefully others can provide some recommendations, but if you want to check the ASUS U.S. 'Where to buy' site, any of those resellers should be able to order the ASUS 180w adapter if you want to check their sites although not all may sell adapters/accessories, etc.
http://promos.asus.com/us/where_to_buy/?_ga=1.15859123.481536228.1449680678Hope this helps some and feel free to discuss if you have any questions. Thanks.