Issue with gear box

[Knipples]

First of all ****ing car! Its cost me the best part of a grand the last year, and now its breaking again.

Basically it hasn't liked going into second gear for quite a few months now, but nothing that I couldnt sort with a bit of brute force. However now its refusing to go into 1st gear at times, to the point where I physically can't get it in gear, and am going round corners in 3rd gear because I cant get 1st or 2nd.

Someone mentioned that it might be the little bit of plastic that you select the gears into, which I am really hoping it is, because that doesnt sound expensive, is there anything else it could be? Surely if the gear box was dying it would be a different problem that I am having.

Need to get my Dads mate to look at it, because I just dont trust garages (being a woman) but its getting to the point I am hurting myself trying to get it into gear, and scaring myself because I cant.

Any advice would be useful. 52 plate corsa sxi (no corsa jokes thankyou please )