In this work we have investigated magnetic properties of (C2H5NH3)2CuCl4, a metal-organic, magneto-electric multiferroic. Measurements of DC magnetization, temperature dependence and hysteresis loops, showed an antiferromagnetic transition at 10.2K and existence of anisotropy. AC susceptibility showed no frequency dependence and from analysing the temperature dependence of nonlinear susceptibility we concluded that (C2H5NH3)2CuCl4 crosses over between different regimes: 2D Heisenberg→3D Heisenberg→3D Ising.