Institute of Engineering and Technology (IET), Dr. A.P.J. Abdul Kalam Technical University

Yes, you can get admission in IET at this rank. All the best.

No, you cannot get a government college with this rank.

Yes, you can get gov colleges and there are 50% chances for IET.

Here is the seat matrix for IET Lucknow. You can get admission here:
Chemical Engineering 60
Civil Engineering 60
Computer Science and Engineering 60
Electrical Engineering 60
Electronics and Communication Engineering 60
Electronics and Instrumentation Engineering 60
Information Technology 60
Mechanical Engineering 60

If it's about placement then you can go for CSE, you can choose any of the colleges mentioned above. Anywhere CS/IT students get easy placements.
If it's about location. Lucknow is much better than Sultanpur in all aspects.
IET-Lucknow has a better campus than KNIT. Well, finally it all depends on your interest. As you already passed out 12th and if you're from CBSE board, you have already studied computer in last two years (I know it's option, but then also )
If you want to go for government jobs, just go for civil engineering, if you want to work in private sector, go for CSE.

UPSEE 2018 College Predictor
Use your UPSEE 2018 rank to see where you can get admission at the link provided below:
See the courses, colleges & rounds you may crack
The result is based on admissions data of UPSEE 2017
Get resources & insights on colleges & courses
https://www.shiksha.com/b-tech/resources/upsee-college-predictor

Congratulations on your excellent rank in UPSEE. Yes, you can easily get IET-Lucknow in computer Science in may be 2 round or 3 round of counselling. Do regular visit to official website of UPSEE counselling, for further updates about the counseling dates. Do like if answer is helpful.