GSM antenna CPW design
This is not correct.

You should try and use your second layer as ground. The ground should be continuous underneath the CPW line. You should also use the correct thickness in your calculator, in your case, using the first and second copper layers, the dielectric height would be 0.25 mm. You will find that as a result you can get much thinner and smaller G-CPW lines.

In addition, it seems like you placed your matching components far apart. You want to place them close to eachother so they "look" like one complex component connecting two bits of transmission line, and do this as close to whatever you want to match (output of the GSM module to 50 ohm? Antenna to 50 ohm?). 

In addition, why do you have a resistor in your RF path? Using lossless components (ie, capacitors and inductors) will result in lower losses. A resistor will match by just dissipating the excess energy as heat.

To answer your final question - if rotating the module is possible, then you could do that to avoid losses (FR4 is a quite lossy substrate), though I doubt they will be very high at GSM frequencies.