it's a good idea to revise the elementary maths from the school textbooks,but I would suggest not to waste too much time on those. just learn the basic principles. GMAT embeds those basic principles with advance logics. you may try this plan after you finish revision of textbooks .
Level 1: Only PS of Princeton and OG 11 first 100 qstns
Level 2: Both PS and DS of Kaplan, SETS,OGs(all qstns)
Level 3: Quant section of MGMAT tests
download an excel sheet named "TestGrid4GMAT" from enips(don't remember exactly). You can time your practice sessions using it. If you are not able to locate it, provide me your mail id,I'll forward it to you.
Since that thread is quite old, I thought I'd mention that I created an Excel file that corresponds to the GMAT Official Guide (12th edition). It lets you track your progress and it helps you identify weaknesses in certain areas.
I call the file the GMAT Prep Now Improvement Chart and you can find it in the Resources section of my site (GMATPrepNow)