Good thing abt E372 is that you can use MDMA ( V11~latest) to chk your area's signal (RSSI) and also your Cell ID.
With this info on hand, you can knoe exactly where to place the modem to get better signal , by using an extension usb (USB3.0 better) cable. A TP Link MR3420 would be much better as the Router will sufficiently power the Cable and Modem with 1A of electrical power ( if via usb port of the pc/lappie ~ 0.5A only)
Your current MiFi is power by battery, the lower the battery the signal will degrade , hence the speed sucks.
In areas where signal is not that good, esp East Malaysia, MiFi is not suitable because the signal is not as strong like some Metro areas of West Malaysia , namely Muntri st Area ( Penang ) PJ area ( Selangor) Dengkil/Nilai ( Near Putrajaya) and ofcourse Putrajaya itself. What more a MiFi's battery will slowly degrade as usage gets longer hence the signal also degrade and speed plunge.
E372 have antenna port to accept External Antenna to boost up the signal, you can use a Panel Antenna to get better signal/speed. Its easier to use compared to a Yagi where you have to point directly to the Tower location. I know a case where the user use an Antenna Signal booster to
s"suck" signal 20KM from the tower, He spent a few thousands to acquired the relevant equipment because if not he would have to drive 25KM from his home to have internet access and you knoe those roads in East Malaysia kampong is not that good too........