is GMAT material good enough for GRE? Shifting to GRE

Hi,

I have given GMAT and scored a 640, 47 Q, 31 V. This was in jan. and this score is not good enough for the schools i am targeting for this session.
my GMAT was scheduled for march end but was cancelled and with the new format i am considering making a switch to GRE.

I wanted to ask:
1. would GMAT material stand good for GRE as well? I'd add to it vocab resources and get hold of the official GRE book as well. or otherwise? I would have a month at hand to prepare and give GRE.
2. Are there any crowdsourced/GMATclub resources for GRE as well?

Thanks