You can get replacement cables from amazon, but you need to now what you are doing.
Or just buy a new one, the PSUs are not expensive - but they don't seem to last long.
If you don't have money for a new charger then you definitely don't have money for a new computer and looking at the handy work done so far you you are about to need a new computer. Since you obviously don't know what you are doing you really need to find the money and purchase a new power adapter.
If you can't afford a new charger you then you definitely can't afford to lose your house to a fire.
Buy a new charger.
On a sidenote, buying a premium, high-priced laptop and not having money to replace broken parts is kind of like buying a Ferrari without the income necessary to put gas in it.
First off that is a very bad idea so absolutely not! Your likely to either fry a fuse in the main power brick and completely kill it or start a fire by doing that.
Yes it is possibly to repair it but as others mentioned you are going to need to purchase parts, soldering equipment and tools to take apart the charger. This will likely cost more than buying a new charger from Apple. With electronic repair experience and the right tools it is not a difficult repair but if you are new this type of work it is a side project at best. This is not something you should be relying on if this is your only charger.