Hi
Glad to see that you are all set to prepare for the GRE.
Here is one Commandment that you need to follow while studying for the GRE - Anything that is not official is not reliable. So stick to official GRE practice books only! You can use the GRE OG 2nd edition and GRE Quantitative review to start with your prep.
These books cover the basics that are required for GRE Quant. Remember GRE tests your reasoning and basic math skills only. So don't worry too much if your math skills are still raw. The most important aspect when you solve a GRE question is to analyze which theory is being tested in the question. This way of strategizing your prep will help you understand the concepts better.
All the best!
P.S. If you would like a Quant guide on GRE inequalities, you can find one on our CrackVerbal website. Inequality questions have taken many test takers down a slippery path, so you may want to keep that guide handy