you could try an online image enlarger service but if you don't get at least passable results you may need to spend time and money using something like photoshop and/or third party plugins such as :https://www.on1.com/products/resize/...SAAEgIKT_D_BwE

whichever way you do it, don't try to increase it all in one go, increase it in steps - interpolation is a fancy word for guesswork - the less the program has to guess during any one pass the better

you may get better results if you start with an image copy that does not have antialiasing; that said, some sharpening along the way may help if you leave it on; but it depends on the source material so without seeing the image, and knowing by how much you need to resize it, its difficult to say more