The first thing I'd like to do is suggest that you don't let anyone rush you through this process. Yes you are meeting with your real estate agent on Monday but you have until the closing or settlement date to come up with an insurance policy that has been paid in advance for one year. So don't let anyone rush you with this, including the real estate agent. Take your time and do your homework on these newer, smaller companies.
Also, don't buy this house unless you can confirm that it has updated electrical, plumbing, HVAC, and a new roof that is going to be acceptable to your new insurance company. If any of these aren't up to current standards you are going to face a nasty surprise when you try to get Florida home insurance for this residence.
A home built in 1940 at age 69 is going to be one of the most difficult to find coverage for - even in an inland county like Orange.
My estimate for a home of this age is around $1,700 per year - driven mostly by the age of the home - but it will depend on the insurance company's view of the upgrades that have been completed. Use an independent Florida homeowners insurance agent to help you with this and answer all of your questions.
I'm not against the online quote generators for Florida insurance but the problem I have with them is that they don't show you all of the companies that are writing new homeowners insurance business in Florida. Here is a site that I saw in every single Florida newspaper after the announcment that State Farm Florida was leaving the state:
http://www.homeinsurancebuyers.org/
http://www.homeinsurancebuyers.org/FindingPrivateInsurance
http://www.homeinsurancebuyers.org/PurchasingTheBuyersGuide
It helps you find, screen, and contact all of the companies still writing new business in your county and is the only way I know of in this crazy market to make sure that you are getting a quote from each and every company that wants to insure your home.
And the best part is that the site provides a rating to each of these companies so that you get a much better idea of the newer, smaller, shakier companies to avoid.
I suggest that you check it out.
In the meantime, don't let anyone rush you with this home purchase. And make sure that you get a good inspector to check that home out. If anything in that inspection around the major systems come up short like the roof or the major systems - don't buy it!
Best of luck to you!