Need some advice on signal booster 4G/LTE ?

Hi all,

im new here :) i don't own any Netgear products at the moment but am thinking of purchasing some, but here is my issue. Early on i was on eBay, i seen a Sunhans signal booster 1800 MHZ LTE booster the seller is based in South Korea and am not sure if i wanna take the plunge as I've never had a outdoor indoor mobile phone signal repeater booster. 

So then i jumped onto Amazon i came across the NETGEAR DC112A my issue is, i'm on UK 3 Network soon as i step outside my house, my smartphone jumps onto LTE and internet is really fast.. But soon as i walk in i lose all signal. For example the kitchen there is no signal if there is its real patchy i cant really take calls in the kitchen. Same goes for my living room as calls drop and internet takes for ever to load up pages same issue is in my bedroom..

So my question is do Netgear sell a router or product that will boost the LTE signal ??? spefically that will boost 1800MHz (Band 3) ? i'm not interested in sim slot or hotspots, i need a signal booster ? is this possible ? Can some one please advise me i will be very grateful..

Thanks..