Your Raster seems to have no SRS assigned. So first of all you have to find out the native SRS of your raster. That can be tricky and difficult. See Layer Properties -> Metadata and search for Layer Extent. From that on you need to find matching Projections for your region. After that, it's basically trial and error.
When you know the correct SRS, you can set it on loading into QGIS. If you want to make the change permanent, you can use the tool Raster -> Projections -> Assign Projection. Choose your file and the correct SRS and press OK.
When you next load the raster into QGIS, it should be in the correct the position.