Need some help estimating profitability

[x_Pulsar_x]

Hey guys, so recently I got into bitcoin mining and on my GPU (R9 290) I'm getting around 25MH/s which is generating around 1.3mBTC (0.0013 BTC) per day, giving me around £2.50 per day revenue. I was looking at a Bitmain Antminer U1 Bitcoin ASIC Miner USB 1.6 - 2 GH/s, which costs around £50 on eBay. Now if this thing mines at 2GH/s for instance (2000MH/s) would I make 80 times more money because I can process 80 times the number of hashes per second? (2000/25 = 80). I know this sounds stupidly dumb to ask but the calculators I have used are all wrong when you put in 25MH/s and tell me I'll make practically nothing, whereas when I multiply the number by 86400 I get the correct amount I generate per day, which suggests it MIGHT be correct. I'm probably dumb for asking this but I would really appreciate some feedback from more experienced users. My appreciations.