You can do it yourself. You will still need to get an alignment afterwards though. Where abouts are you located?
In the U.S. you can get some amazing deals on alignments at firestone
To do the inner tierod, you will first need the part obviously. If you are going to do it yourself, buy the part first, you will need it to make sure you rent or buy the right tool to remove it. You could use a large crow foot wrench, or if you can find it, its basically a 16" socket that goes over the whole thing. You will need to cut the fastener that holds the dust boot on. You will need a special tool to install a new clip if you go that route. you basically back the tierod off till you feel some resistance, and then crank it really hard to break the rivet that locks it on. Oh and you will have to remove the outer tie rod end also. that is simple and takes like 10 minutes. Installation will be opposite of removal, your new part should come with a small rivet, that once the tierod is tight onto the rack, you press on it and it locks in. install the boot, not sure if other people use zip ties or if they use the special metal ties that ur supposed to. other people might have more information, but i would assume the procedure is fvery similar between your g3 and my g1