The best way to heat up a tamale is to steam them. Did she give you directions?
Also, are you on a diet? Because they can be VERY fattening! It is the lard that they use in the masa that is a killer. Yeah- lard. Unless you have some made by someone that is of a healthy mindset and has substituted it.
Don't get me wrong, I love tamales, but I don't eat them very often because of the calorie punch. Around these parts they are a tradition at christmas.
I usually serve them with black beans and some homemade mexican rice.
Depending on the tamale I will also put red or green sauce on them.