Right or wrong, I bought this. Honest opinions please. Tell me what you think and what I may need to upgrade. The seat? OUCH! I'm guessing the bike is from the 80's. How can I find out for sure?

Description:

AN EXCELLENT LOTUS 12 SPEED MIXTE EXCELLE. THIS BIKE IS IN FULL RIDING SHAPE IT IS A SIZE 53CM AND THE STANDOVER=31 INCHES. THE RIMS ARE STRAIGHT AND TRUE. HERE ARE THE SPECS AS FOLLOWS: HEADSET=SHIMANO, HANDLE BARS=SR ROAD CHAMP, BRAKE LEVERS=C-STAR, BRAKE CALIPERS=SHIMANO 500 AND TOURNEY, FRONT WHEEL=27 1 1/4 UKAI, REAR WHEEL=SAME, HUBS ARE SHIMANO VIA, SHIFTERS= SHIMANO 600 ALONG WITH BOTH DERAILERS, PEDALS=MK THE FRAME HAS NO CRACKS OR BREAKS.