how many Muslim vote in Israel elections now ?
Don't know. A little less than 20% of the population. They're educated, work for a living, and participate in society so I'd guess that's around the vote.
Any adult citizen of Israel who happens to be a Muslim may vote. That includes any Muslim living in the pre-1967 borders plus any Muslim living in territory Israel annexed since then (Golan, eastern Jerusalem) who has chosen to take Israeli citizenship. Many Jerusalem Arabs haven't chosen to do so and have permanent resident status instead. They have no vote.
Currently Israel's population is 5.3 million Jews and about 1 million Muslim Arabs. I can't tell you what percentage of each group is of voting age without doing a little quick research. Considering the only reason I'm on at this hour is insomnia this isn't the best time for me to do that.