Installing a new sink in a kitchen.....

We are moving into a new rental that doesn't have a sink in the kitchen. Its a relatively new house but they didn't put one in because there are a few sinks in the garage area I think. 

I asked the landlord if we can pay to get one installed and presume that I can simply buy a sink and vanity unit at homepro and ask a tradie to plumb it in. Has anyone done this recently? If so how much would it cost. 

The question is which wall would we install the sink. There are 2 options. Firstly the main wall where there is a window faces the back yard. The 2nd option is an internal wall adjacent in a dark corner - on the other side of the wall is a toilet and sink (with existing plumbing). Would it be best for the guy to install it against that wall so that he can hook up the pipes to the existing ones?

Im clearly clueless about plumbing and would appreciate your advice. At our current rental the sink water leads to a pipe outside which empties out onto the grass. The birds appreciate it and so does our dog sometimes. 

Please help.Im interested to know what the total cost would be to do this?

thanks