@Hillsalt, do the simple thing, get a structural engineer / surveyor in to give you a schedule of works, preliminary costings and to oversee the project. Unfortunately there isn't enough information in your post to give any kind of meaningful answer.
We knocked down the wall between our kitchen and dining room to make a big kitchen. It was very messy but my husband did the job himself. It took a couple of days. He had to get an RSJ support and he put that in before he knocked down the wall. It was very heavy and we had to round up 6 or 8 able bodied men to lift it. He hired these supports to keep it up till it was fit properly. It only cost a couple of hundred. The only thing we had to buy was the joist.
That was 3 years ago and the house hasn't fallen down yet!!!
We knocked through double doors from our sitting room to kitchen recently. Got a builder to do it, cost €2,600 for the work (this also included some other carpentry work in the kitchen). It was quite a messy job, dust everywhere and had to move out all furniture, but well worth it, has brightened up the place considerably. An concrete support was fitted. The whole job only took 3 days.