Hello community. I want to start off by thanking everyone for their input. My lawn is a mess (I bought it this way :)) I'm asking this community because its a strange combination problem.

It has the following problems:

1) Sloped too much at the bottom, needs more soil to level
2) Front half (adjacent to house) has reasonable lawn. Bottom half was full of weeds or bare patches

Things I have already done:
1) Roundup the weeds as much as possible in the fall. I'm sure the seeds have already spilled.

What I want to do:
1) level the lawn
2) Sod

I don't know how to accomplish that. I was thinking (for springtime):
1) Retill the soil
2) Rake out the grass
3) Add soil and rake out to level
4) Wait a week or two for weeds to come up, Kill them,
5) Sod. Water appropriately.
And to do this all in the spring.

After scouring the posts, I've seen a mix of everything. To retill, not to retill (I need to! get rid of the grass and level). To seed or to sod (sod, because i'll be planting in spring).

Please help. How do I get this done? I want to sell the house in late summer.