In Floor Heating Temperature

What can I do about different floor temperatures in a duplex home/apartment ?
I live downstairs and I sub lease the 2nd floor which has no thermostat. 74 degrees is too hot for me…but any lower and tenant will complain of cold. Heat rises but upstairs is colder. I’ve tried a few tactics such as closing my vents and lowering the temperature slightly hoping for 5% more of total heat for upstairs. Still cold for her !
Any suggestions for a penny pincher with moderate handyman skills ?
portable heaters/ space heaters are a good choice if you dont mind moving it with you to each room. theyre also really cheap and easy.
http://www.amazon.com/Soleus-Air-MS-09-Oscillating-Radiant/dp/B00009RAVP/ref=sr_1_18?ie=UTF8&s=home-garden&qid=1263704526&sr=8-18
TileFlow Calculation of Airflow and Temperature Distribution in a Raised Floor Data Center 2