You have a good score on the Quant section so you don't to worry on that front. Since you're targetting 40 on the Verbal section, you need to improve by another 15 points and frankly speaking this kind of improvement is a tad difficult within one month. However, as you said that you didn't prepare at all on your attempt, so your score of 25 might not be an actual reflection of your capabilities and you may get your desired score. However you'll need to be very systematic in your preparation.
Regarding the books you have mentioned,
MGMAT SC Guide is a good book but as you'll read here most of the people prefer using it in conjuction with the SC Grail. Using both books together will really crystallize your concepts. For CR,Powerscore CR Bible is supposed to be better than
MGMAT CR Guide but I think you should be fine with
MGMAT CR Guide if you already have it.