Converting my duplex to all-electric?

I own one side of a duplex, along with another gentleman who owns the other side. We've both consented to convert it to all/total electric. I've called an electrician, and the electrician said that it doesn't matter who converts their side first or if both sides are done at the same time. The other owner is out of town for a few months and I have a single family who's ready to move in my side and pay me rent. My side is a 2-bed/1-bath, gas stove and central air & heat. The duplex was built either as a house or 2 unit apartment back in the 60's and it's located in Atlanta GA. Renovations have been done to keep it looking up to date and nice and pretty on the inside. My asking price is $450 per month. But my tenant proposed to pay $650 or a little more per month if I converted it to all electric because he cannot afford a gas bill that may or may not varies every month, which make perfect sense to me. The electrician hasn't given me a quote or estimate yet. What can I possibly expect and depending on the estimate the electrician gives me, what would be a fair price to charge my tenant? Please advise.