not all people are trying to recover the cost of equipment with money..
releasing stress by going out taking pictures, or ability to master the camera for family documentation, may be their break even cost :)
if you need F2.8, keep the tammy.
if you need < F2.8 and can live with 50mm, keep the 50mm, else try 35mm.
then once budget permit, trade 18-135 with 18-200.
on close focus distance at 200mm, 18-200 is almost down to 135 anyway.. :)