If you got extra money then you can either get a gazeted area for swiftlet farming, shop that are make for this purposes where you can get loan which you need to pay 10-20% downpayments and if you got more then RM 200,000 then you might as well get a land and built it at your desire locations.
Normal market price per sq feet in the market are roughly RM 65 per sq feet excluding land price if you are building from scratch. For internal renovations only estimated RM 20 per sq feet or less. Price are vary depending on job require as well as quality of products. Above all this, one thing you must always remember is tweeter, make sure you buy a god quality types cost this is where the bird attracted to it. Get the one with built-in condenser and sharp soud produced.
In Malaysia, big cooperate company are going in a big way by investing millions of ringgit in project developments for swiftlets or ecology park. This create lots of opportunity for new player to be involve.
How much you want to invest is all up to you at the end