Lexus 91 Es250 A/C replaced update = not cold!

Car: 1991 lexus es250 120,000 miles.
relpaced compressor
condensor and dryer
charged with r12, about 2 cans (what mechanic listed)

UPDAte: I replaced the climate control dash part but it didn't imporve the situation.

I took my 1991 Lexus to a local repair shop to get my A/c repaired (it blew hot air). They told me I had to replaced the compressor. I did and they used a remanufactured one. The A/c worked perfect, but stopped working 2 weeks later. It started to blow cool air, not the usual cold air. I took it back and they told me I had to replace the condensor ( I was upset at this point). After replacing that, it started to work again sufficiently.
only a week after, it started to blow less cold, more cool and stayed this way for two months until now. I measured the tempture after letting it run and it registers 76-79 degrees under medium fan speed. The higher the fan speed, the less cold it blows.

Details: the compressor comes on. (Doesn't make any harsh noises like the original one did)
the belt is at correct tension (took in for a diff job last month and belt was tighted accordingly)
condesor and dryer is new.
all hoses seem intact with rubber housing around it.
driving on highway does improve it.
when car is cool (like in a garage) and I drive off, it seems to work a little bit better (but not like a normal car). When car is hot, I cook.