cpu vs gpu

Hello, Right now I have a pc with a i5-3470 with a gtx 770x and 8gb ddr3 ram. A friend of mine offered me a deal on his 5 year old I7 4770k + z87 asus maximus formula vi for ~180£ Should i go for that or with the same money buy a new gpu?(prolly a gtx 1650 or 1060?) Wich would give me a bigger...