3D renders for a house

We have a house in Malta for which we'd like to do a few 3D renders, to be able to sell it to potential buyers who will buy the property in unconverted state, and then they can finish it themselves. The 3D renders are required to show potential buyers how the house can look once finished. 

I am attaching to this project the Proposed Layout of the house in PDF and ACAD versions, so you can better understand the property.

We are planning to prepare 3D renders for the following areas of the house:

First floor level:
1. Kitchen / Living / Dining 
2. Back yard showing the outdoor area 
3. Bedroom (this would have to retain the existing architectural features as it can't be demolished)

Second floor level:
1. Bedroom with walk-in and ensuite

Item (3) of the First floor level above needs to retain existing ceiling features, due to cultural heritage. Photos of this room can be provided.
The other items will be completely new construction and can be finished in modern design, so no need to see photos of the existing state.

At this stage I would like to know the cost involved to prepare the above-mentioned renders.

Also please let me know if you can propose to me interior design options from your end.

Thanks.