Remodel home

Hi, I have an independant home build on 165 sq yd, 900 sft built up space . This was build 20yrs ago by a local builder and now I want to renovate and remodel and add two more floors but keeping costs low.Hence I am looking for an architect who can achieve this and help me with the build materials to be used to keep the costs low at the same time make this a home more comfortable for my aging parents. First floor to have kitchen and 1 Master BR with ensuite and second floor can have living area and 2 BR with ensuite with an open terrace on 3rd floor