Need help to get in the 690-730 range...

Figure I might be able to help you out a bit -- verbal tends to be my strong point, it's the quant that I struggle with!

-Start with the Kaplan Comprehensive book. They don't get into much detail on the verbal, but the strategies are good and it's a solid overview that should really help with any question of moderate difficulty.
-After the Kaplan book, you can definitely benefit from reading the Manhattan GMAT guides on Verbal. If Sentence Correction is a problem, they have one of the most comprehensive guides out there (though frankly it's very thick and takes a lot of time to get through), and their critical reasoning strategies are pretty robust.

Also, never underestimate the power of process of elimination on the verbal. Almost 100% of the time on Sentence Correction, I have no idea whether the original statement is right or wrong until I eliminate the 4 wrong answers. Probably close to that percentage on the other question types. I've been consistently scoring around 44-45 of practice tests so it seems to be working for me.

I wrote the following advice up on someone else's post yesterday, perhaps it can help you:

(1) Practice smart, not hard:
It sounds like you've gone through a mass of material, but how much time did that take you? If you're aiming for a drastic score improvement, you need to spend quite a bit of time on each section that you're weak in. Spend MORE time on FEWER questions in your practice, making sure you're 99% confident in your answer before you even peek at the explanation. Racing through questions and material might cover a lot of ground, but very little of it will stick.

(2) Read non-GMAT material:
GMAT material can get very tiresome after a while, and I think one of the best things you can do is read material from other sources but put your brain in a GMAT mindset. One of the best publications that I've found for this is "Scientific American."

(3) Get the mindset (even with non-gmat material)
For me, the verbal isn't as much about knowledge of concepts as it is about mindset. You have to approach every question (except sentence correction) with an eye of very critical analysis. You need to have ideas about what the answer will be before you even read the answers. For example, in CR, the answer choice for any assumptions, strengthen weaken, or conclusion question type (most questions) will almost ALWAYS apply directly to the conclusion -- if the answer choice doesn't relate specifically to the conclusion, just forget it immediately. Only re-read it if you can't find one that does.

The more you practice this mindset, the easier it becomes. Because almost all questions follow the same basic structure, once you crack it, your score will skyrocket.

(4) Sentence correction -- practice practice practice
The sentence correction is a little different from reasoning and reading because it doesn't necessarily follow the same 'mindset.' Especially if you're ESL, this might be the hardest to improve on because of idioms. Just practice a lot of practice questions on this and make sure you understand the answers before you move to the next ones. Worst comes to worst, on the actual test, you can narrow it down to a few choices and take a guess quickly in order to give yourself more time on the other sections.