Basically what Juro stated above is good.
Do you have breatheable waders which are large enough to wear the long underwear and fleece pants/bib ?
Thats what I am using now and I like it better than the neopremes.
Get some Smartwool socks and liners.
Galyans has some decent stuff but I think the best in our area is probably Bass Pro Shop in Gurnee. Their hunting waterfowl gear is awesome and is the same stuff we need for cold weather GLs fishing.
Thats up your way check it out.
P.S. In April the water temp will be in the high 30s low 40s and air temps 40-50s. Could be 30-40 air temps though to.