As others have said - Roda is a better bet than Corvera for rentals but having said that Roda is not that brilliant at the moment due to recession. Now might the time to buy cheap - but people expect to pay very lettle as well to rent.
For a 2-bed apartment you need to budget €2500 a year to pay for Community, Entidad, IBI and renters tax - and that's on the cheapest phase (Phase 2). Budget nearer €2800 for Phase 1 and 3.
There is another thread from April with info on as well
http://www.eyeonspain.com/community-forum/32107/is-there-a-market-for-holiday-lets.aspx
As Mollusc and Sandra said, the market is extremetly cutthroat on Roda and is costly in terms of both time & effort and cash to achieve lettings. Budget about £700 pa to advertise on the 2 biggest sites - although some now offer commission based advertising although you don't get paid until after the let.
If you don't live on site then you will need a Management Agent. They will charge a minimum of €300 pa just for key holding and then you will need to pay for cleaning between lets of about €100 a time.
Also factor in that some idiot renters will turn the air-con on 24*7 in the summer which will cost you in the region of €50 a week.
It is slightly easier to rent out long term but then you wouldn't be able to use it for your own R&R and at the moment a 2-bed long term rental is only fetching at most €450-500 pm. I know of one that has just rented at €400.
You will find it hard to even cover the above costs - let alone make a profit in the current market. And if you have a mortgage to pay as well then you will never cover costs.