If you have inventor or AutoCAD, then go that route. Inventor can open a Solidworks assembly file-although it usually supports upto one release back from the current one) and it has hooks directly into Maya. You might also wan tto look at Inventor Fusion. I think, it can attach a Solidworks file and port it to Maya.
If you have AutoCAD, you can export your Solidworks assembly to ACIS format, use the acisin command to bring the 3D geometry in. (I think you want to select ACIS 7 or earlier) and then import the AutoCAD drawing into Maya.
If you don't have Inventor or AutoCAD, you can try using Draftsight to create a dwg you can import into Maya. It's free. http://www.draftsight.com
While I am not familiar with Maya, I have experience getting models out to rendering applications. You can expect to recreate any materials that were used in SolidWorks, as there is no standard for materials exchange from CAD applications using nurbs formats. Its possible you might get some textures out using VRML format, but you may not get useable UVs.
If you are having problems getting good meshes by importing the IGS files into Maya, you could try a conversion program such as Polytrans from Okino. They have translators for SolidWorks and other nurbs formats, and they have a demo available to see if it will work for you. Alternatively you could use Rhino for the conversion, which generally produces good meshes from nurbs files. I don't know if Rhino can read SolidWorks files directly, but you can get import IGS or other nurbs based file.
Without going to another piece of software, you could try exporting STL or VRML (WRL) from SolidWorks. The issue here is that the mesh will be triangulated, which may not be optimal for rendering in Maya, and control over the resolution of triangulation in SolidWorks is less than ideal. You can get long spikey triangles which often produce rendering artifacts. Its possible to break up the sufaces to minimize this problem, but that adds time to the process.