Do you calm things down at home OP in the build upto bed time?
I get where your coming from I was a single Mum to 4DC including a new born baby and breastfeeding it can be really hard.
What's worked with all of our 5DC is calming everything down for about an hour before bed time,so no sweet treats or sugary drinks something calm on the tv then I'd do bath time,bath,wash hair,brush teeth get them dried and dressed,all of mine have supper and then I'd take them upto bed.Then I'd tuck them into bed and read a bedtime story or 2.
Mine go up at different times now because they're all older but being as yours are both so young and close in age it may actally be easier to put them to bed at the same time.Calming everything down upto an hour before bed time so that they get used to a bedtime routine and know what to expect,taking them to bed together tucking them in and then reading them both a story or 2.Mine used to fall asleep whilst I was still reading the story or just as I finished it.
Like another poster suggested black out blinds/curtains are a God send,a night light if they need a light on rather than a overhead bright light can really help them to settle alot quicker as well.
I've also found making sure there aren't things like a Tv/Ipad ect in close proximity in a child's bedroom to young children when your trying to get them to settle to sleep helps alot.
If you stay in the room until they fall alseep try to be as boring as you can,no talking to them,making a fuss of them,making eye contact it really does work the boredom seems to make them fall alseep alot quicker and they're more likely to sleep through the night as well.
Don't forget it could be four steps forward and then two steps back but don't feel defeated you can do this and a good nights stress free sleep will be so much better for you and your DC.