I have to take GMAT® but I don't know how to prepare

[Zeyneparslan]

Hi everyone,
I must take GMAT in 3 months because I want to apply for 2008 fall.So I have to study a lot but I don't know how to start studying it.I took TOEFL it was 88.it isn't so good.it is possible for me to take TOEFL one more time.However first of all,I will study GMAT.There are a lot of things to do but there is nothing figuring how to start.Please give me some advice.I really apreciate your advice....
I don't think to enroll a course I want to study myself.Is it enogh to study myself?
which book is really good for me to study myself?my target is 700 because of my low TOEFL score:-((((I have to make a great effort for GMAT....
Thanks in advance,,,,